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First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

First thing I would check are the valve clearance. This manual may help you out. https://resources.kohler.com/power/...1.1295208345.1687544055-1693047200.1687544055

Thanks for the suggestion. I took off the valve covers and a pool of oil spilled everywhere. I was ready for a little bit, but this seemed excessive. I checked the clearance, and all four were spot on. I resealed with Permatex Ultra Red. In an hour, I'll torque it down. Will run again tomorrow.

Hate to say this but did you removed the shroud and check the crankcase bolts to see if any were loose? The Courage engine had a big problem with these bolts coming loose. If they are not tight as the engine heats up and your timing might be changing causing a loss of power. I’ve never heard of loose bolts causing this problem, but this engine has had unusual problems in the past. Also it might be worthwhile to purchase an inline spark tester and insert it into one of the plug lines, looking to see if the spark changes when the problem occurs. Will need to do both cylinders separately, unless you get to testers. If the spark changes you may have a coil which is starting to breakdown. We need to figure out whether it is a spark or fuel issue. If spark stays strong and consistent, we go to a fuel problem.

Rivets said:

Hate to say this but did you removed the shroud and check the crankcase bolts to see if any were loose? The Courage engine had a big problem with these bolts coming loose. If they are not tight as the engine heats up and your timing might be changing causing a loss of power. I’ve never heard of loose bolts causing this problem, but this engine has had unusual problems in the past. Also it might be worthwhile to purchase an inline spark tester and insert it into one of the plug lines, looking to see if the spark changes when the problem occurs. Will need to do both cylinders separately, unless you get to testers. If the spark changes you may have a coil which is starting to breakdown. We need to figure out whether it is a spark or fuel issue. If spark stays strong and consistent, we go to a fuel problem.

Click to expand...

Timing is controlled by the flywheel key. The shaking engine is probably loose or lost engine mounting bolts. The Kohler Courage is a dog and has several problems. Read up on it online and definitely check the top cover engine bolts for tightness under engine shroud.

Valve timing is controlled by camshaft, which could wobble if the cover comes loose. Slight change in valve timing can cause loss of power.

Rivets said:

Valve timing is controlled by camshaft, which could wobble if the cover comes loose. Slight change in valve timing can cause loss of power.

Click to expand...

I realize that valves are controlled by camshaft. Thought you meant ignition timing.

This will also happen if one cylinder is not firing
IT will run sort of OK for a while although being a bit under power then will overheat .
From dead cold start the engine and lightly touch both exhaust pipes.
If one is substantially hotter than the other then that side is not working properly .
Let us know what you find

Rivets this is not the bucket engine. It just a Briggs crankcase design wise. It was the Kohler single cylinder bucket engine that had the closure plate bolt coming loose over time. Some of those actually broke the cylinder off the crankcase until Kohler re-enforced the area.

Rivets said:

Hate to say this but did you removed the shroud and check the crankcase bolts to see if any were loose? The Courage engine had a big problem with these bolts coming loose. If they are not tight as the engine heats up and your timing might be changing causing a loss of power. I’ve never heard of loose bolts causing this problem, but this engine has had unusual problems in the past. Also it might be worthwhile to purchase an inline spark tester and insert it into one of the plug lines, looking to see if the spark changes when the problem occurs. Will need to do both cylinders separately, unless you get to testers. If the spark changes you may have a coil which is starting to breakdown. We need to figure out whether it is a spark or fuel issue. If spark stays strong and consistent, we go to a fuel problem.

Click to expand...

Just to clarify if I may, the issue with the loose bolts was on only Courage single cylinder engines where there was no removable oil pan and you got to the inside of the engine by removing the top closure cover of the engine. Those did indeed have some loose fastener issues.
Ooops... Just noticed Star already addressed this.

Tiger Small Engine said:

Timing is controlled by the flywheel key. The shaking engine is probably loose or lost engine mounting bolts. The Kohler Courage is a dog and has several problems. Read up on it online and definitely check the top cover engine bolts for tightness under engine shroud.

Click to expand...

The thing to remember is the Courage single cylinder was the dog. The unfortunately same named Courage twin was a very good engine and was in many ways simply a Command twin with solid lifters.

MrLarkins said:

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

Click to expand...

I'd suggest removing and inspecting the fuel solenoid. Sounds like it could be malfunctioning and about to go out.

MrLarkins said:

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

Click to expand...

I'd suggest removing and inspecting the fuel solenoid. Sounds like it could be malfunctioning and about to go out.

Ran it again today. Issue persists.
To VegetiveSteam: I took your suggestion and check the heat from each side of the exhaust...both cylinders are putting out the same heat.
To Rivets: the crankcase bolts are all tight.
To PT mowerMech: when I turn the key and before the engine cranks (accessory spot), I here the 'click' of the solenoid in the carb. What else can I do to 'check' it?

I'm going to take a video of the issue occurring and post it for your inspection.

What else?

Starting up <--video link

Mower issue: it dies when warmed up. <--video link

buy a pair of red in line spark testers and install them
When the engine is running properly they will glow red/ orange
Watch them when the engine is faultering
If one ( or both ) start to flash then you have an electrical problem
If they remain constant then only flash when the engine get to a slow idle you have a fuel problem
If you can get your hands on an alternative fuel tank hook it up directly to the carb and see if the problem goes away
Either or both
The first step is to work out if the problem is electrical, fuel or mechanical
As for mechanical, tat would be things like a valve guise or seat coming loose
Valve guides are easy to check because the valve lash will be different every time you check it

FWIW I have a fuel tank I got off an old Tecumseh flat head engine that I use as an alternative fuel supply
You can usually pick them up for peanuts as trash & treasure sales, boot sales or mower wreckers .
A customer with motorcycles pinched the tank off one of them and I have even had a customer who used the tank off their push mower

OK, I ordered a pair of red inline testers. Delivery is Tuesday. I'll get back to everyone then. Thanks

When it's warm and acting up like in the video, how does the engine run if you just let go of the levers and sit still? And if it seems to straighten out while sitting still what does the engine do if you move the throttle to idle?

MrLarkins said:

Starting up <--video link

Mower issue: it dies when warmed up. <--video link

Click to expand...

Sounds like it is starving for fuel.
Fuel pump?
Tank vent?
Hot carb boiling fuel?

VegetiveSteam said:

When it's warm and acting up like in the video, how does the engine run if you just let go of the levers and sit still? And if it seems to straighten out while sitting still what does the engine do if you move the throttle to idle?

Click to expand...

From a cold start, it takes around 10min before it begins acting weird. Once I hear the engine take a turn for the worse, I can keep it running by turning off the blades and/or letting go of the handles (to neutral). But after 10min of doing that, it'll die even if I back off and reduce the throttle.

VegetiveSteam said:

The thing to remember is the Courage single cylinder was the dog. The unfortunately same named Courage twin was a very good engine and was in many ways simply a Command twin with solid lifters.

Click to expand...

The Kohler Courage single is definitely worse and has more problems hands down than the twin Courage. That said, I would never say the Kohler Courage twin was a very good engine. In fact, you are the only person I have ever heard that has said that. I am a Kohler guy and fan also, just not the Kohler Courage, single or twin.

The courage range is the engines that the mower companies want to pay for
The command is what the owners actually want
I am a fan of the Courage singles , such an easy engine to work on and the only one that you can change the oil filter without having to clean up a horrid mess or make up all sorts of weird shields to prevent oil ending up allover the belts.
1/3 the time to split the engine which you can leave in the mower thus a big time saver and only 2 spanners to strip the engine as compared to the 9 you need to strip a B & S engine .
When they started to develope the Kohler Krack, Husqvarna simply dumped them down here by the thousands so near 1/4 of the engines I service are courage singles in Husqvarna tractors .
I love them , just a shame that they changed over to the cast crank mid production which played havock with the balance .

well, now I'm really distraught. I went to use the red inline spark plug testers just now, and the crank wouldn't turn. oil was gone! but there is no leak on the mower or the ground! on top of that, the air filter box is FULL of fuel and the air filter is soaked. I took it apart and disconnected the crank case breather hose (see pic), added some oil turned then turned the crank with my hand 1 revolution (it was almost impossible, but once it broke free, it was easy). I managed to start the engine, but fuel started GUSHING out the breather hose! I don't think that's normal. Should I give up and scrap this thing?

I ran it for about 15 mins in my driveway. Fuel is no longer gushing out breather tube, but it is dribbling out still. red light spark plug testers show flickering red lights on both sides of the motor.

UPDATE: I mowed for about 15min, without the air filter (it is soaked with fuel). It did like it has been, fine for a bit, but then starts its thing. This time, after I parked it, I pulled the dipstick out and there was a lot of smoke in the fill tube.

That screams blown head gasket
And the blown head gasket could have been caused by a hydro lock
And the hydro lock is caused by the float valve not cutting the fuel supply off .

In use this manifests itself by the engine running normally when you first start then over time begins to run rich ( black smoke & missing ) till eventually it floods the engine & it dies .

uh, I was afraid of that. I really don't want to tear this motor apart. So, take it to the shop or buy a new mower? or, run this until it completely dies, then scrap it?

Pull the tube that goes from the rocker cover to the fuel pump. Is there any evidence of fuel in that tube?

Head gaskets are about 1/2 to 1 hour each side
carb cleaning actually can take longer but replacing the float valve is a 15 minute job .

VegetiveSteam said:

Pull the tube that goes from the rocker cover to the fuel pump. Is there any evidence of fuel in that tube?

Click to expand...

It's dry.

MrLarkins said:

It's dry.

Click to expand...

Okay good. When it goes to die, will giving it a bit of choke help at all?

VegetiveSteam said:

Okay good. When it goes to die, will giving it a bit of choke help at all?

Click to expand...

yes! I can drive it for another few minutes on FULL choke.

MrLarkins said:

yes! in can drive it for another few minutes on FULL choke.

Click to expand...

In the video it sounded like it was either starving for fuel or getting air it shouldn't be getting. Either way it seemed lean to me. But that's just one opinion.

If that engine has a plastic intake manifold, they have been known to separate at the seam and also leak at the o-rings where it mounts to the heads.

It's only a theory but if the intake manifold was separating, it may need to get warm before the crack opens up to the point it lets in enough air to cause issues. Once the engine slows, the governor would open the throttle plate wide open and I wonder if at that point it's able to suck some more fuel until the governor reacts and lets the throttle plate start closing again and it just keeps repeating itself until the crack opens up to the point even choke doesn't help.

This wouldn't explain some of the other issues you have going on but it could account for part of it.

It is plastic. How can I test your theory?

I've attached some images of the manifold. the seem and top dead center...take a close look.

MrLarkins said:

It is plastic. How can I test your theory?

I've attached some images of the manifold. the seem and top dead center...take a close look.

Click to expand...

Carb spray. When it starts acting up, carefully spray the seam and the ends at the head.

VegetiveSteam said:

Carb spray. When it starts acting up, carefully spray the seam and the ends at the head.

Click to expand...

ok, done. ran it, and when it started to die, I sprayed the seams...no effect. I then sprayed some carb cleaner directly into the air box, and the engine picked right up and rev'd, for a moment anyway. Should I take apart the carb again and take a closer look?

MrLarkins said:

yes! I can drive it for another few minutes on FULL choke.

Click to expand...

This is text book floating debris in the fuel tank blocking off the fuel supply
Next time it stops pull the fuel line off on the tank side of the pump ( if fitted ) and blow back through the fuel line.
If the engine fires right up them either the tank needs a clean or the fuel line has degraded & needs replacing .

bertsmobile1 said:

This is text book floating debris in the fuel tank blocking off the fuel supply
Next time it stops pull the fuel line off on the tank side of the pump ( if fitted ) and blow back through the fuel line.
If the engine fires right up them either the tank needs a clean or the fuel line has degraded & needs replacing .

Click to expand...

how will the fuel filter affect this attempt?

Once it gets bad enough that it dies, will it start right back up?

MrLarkins said:

how will the fuel filter affect this attempt?

Click to expand...

I just makes it harder for you to blow back.
The fuel pump ( where fitted ) has 1 or 2 check valves so you can not blow back through it from the outlet side

VegetiveSteam said:

Once it gets bad enough that it dies, will it start right back up?

Click to expand...

yea, but it won't last

OK, it's a new day. This morning, I disconnected the fuel line at the fuel pump (tank side) and used an air compressor set at 10lbs to blow the line back into the tank...easy enough, and I didn't notice any debris, but honestly, I can barely see into the tank. I took the carb off again, cleaned and checked it (see images),

then reassembled and went to mow. I have 1 acre, and was able to complete the mow without it dying. However, after it was warm, it did lack power in taller grass, and on occasion when turning it acted like it wanted to die. I let off the handles and just sat for a second while the rpm came back up and then continued on my way. After the mow, the engine was smoking (see video-->Smoking ) from what seemed to be the left cylinder head.

If I were to sell this mower to another homeowner near me and tell them about the issue, what is a fair asking price in your opinion. Once again, this is a Husqvarna RZ5426 with Kohler Courage 26HP that needs love. The mower has been well maintained and has 1950 hours on.

MrLarkins said:

OK, it's a new day. This morning, I disconnected the fuel line at the fuel pump (tank side) and used an air compressor set at 10lbs to blow the line back into the tank...easy enough, and I didn't notice any debris, but honestly, I can barely see into the tank. I took the carb off again, cleaned and checked it (see images),
View attachment 65467View attachment 65468View attachment 65469View attachment 65470
then reassembled and went to mow. I have 1 acre, and was able to complete the mow without it dying. However, after it was warm, it did lack power in taller grass, and on occasion when turning it acted like it wanted to die. I let off the handles and just sat for a second while the rpm came back up and then continued on my way. After the mow, the engine was smoking (see video-->Smoking ) from what seemed to be the left cylinder head.

If I were to sell this mower to another homeowner near me and tell them about the issue, what is a fair asking price in your opinion. Once again, this is a Husqvarna RZ5426 with Kohler Courage 26HP that needs love. The mower has been well maintained and has 1450 hours on.

Click to expand...

I'm no help with an asking price but I do have a couple of questions toward still trying to repair it.

I apologize if I've missed it, but have you checked compression? And now after running it and seeing the smoke, what's the oil level?

I don't have a tool to check compression values, but I can say that there is bounce/kickback when I spin the crank by hand for what its worth. I just checked the oil level after letting the engine cool for an hour and it is 1/2 between E & F. I remember it was Full just a couple days ago, but was also filled with fuel as well (remembering it gushing out the breather tube).

Assuming both sides are free of weeds and debris, and all the cooling tin is in place, if one side is that much hotter, it is either pulling much more load, or it is running lean, or it has advanced timing.

if it is pulling more load - find why the other side is pulling less

If it is lean then swap carbs and see if the problem follows the carb or the side. Use some spray flammable carb cleaner to look for a vacuum leak. The other side could have the vacuum leak or be too rich.

If the timing is not adjustable per side, then you can ignore this, but if the timing is adjustable per side check it.

don't discount what a leaking head gasket can cause in mixture and power issues. Look carefully to see if there is any evidence of leaks on either side.

MrLarkins said:

Ran it again today. Issue persists.
To VegetiveSteam: I took your suggestion and check the heat from each side of the exhaust...both cylinders are putting out the same heat.
To Rivets: the crankcase bolts are all tight.
To PT mowerMech: when I turn the key and before the engine cranks (accessory spot), I here the 'click' of the solenoid in the carb. What else can I do to 'check' it?

I'm going to take a video of the issue occurring and post it for your inspection.

What else?

Click to expand...

If I'm seeing this correctly, the engine is shaking and the mower frame is not. Have you tightened the engine to frame bolts?

MrLarkins said:

Ran it again today. Issue persists.
To VegetiveSteam: I took your suggestion and check the heat from each side of the exhaust...both cylinders are putting out the same heat.
To Rivets: the crankcase bolts are all tight.
To PT mowerMech: when I turn the key and before the engine cranks (accessory spot), I here the 'click' of the solenoid in the carb. What else can I do to 'check' it?

I'm going to take a video of the issue occurring and post it for your inspection.

What else?

Click to expand...

If I'm seeing this correctly, the engine is shaking and the mower frame is not. Have you tightened the engine to frame bolts?

Gas cap vent is worth a look.

STEVES said:

If I'm seeing this correctly, the engine is shaking and the mower frame is not. Have you tightened the engine to frame bolts?

Click to expand...

This

kjonxx said:

Gas cap vent is worth a look.

Click to expand...

And this. Once you get the engine bolted to the frame, check to make sure your engine has an adequate fuel supply. Check for loose debris in the tank, check to make sure the fuel pump is good and check for pinched off fuel lines. You have an obvious fuel starvation problem. I've read thru the thread and if you've made sure the carb is not the issue by cleaning all fuel passages then the issue is going to be a fuel supply problem.

BTW, the engine video of the one side overheated was caused by running the engine for an extended period without the fan shroud/blower housing. Any air cooled engine will overheat without that shroud/housing in place.

bertsmobile1 said:

The courage range is the engines that the mower companies want to pay for
The command is what the owners actually want
I am a fan of the Courage singles , such an easy engine to work on and the only one that you can change the oil filter without having to clean up a horrid mess or make up all sorts of weird shields to prevent oil ending up allover the belts.
1/3 the time to split the engine which you can leave in the mower thus a big time saver and only 2 spanners to strip the engine as compared to the 9 you need to strip a B & S engine .
When they started to develope the Kohler Krack, Husqvarna simply dumped them down here by the thousands so near 1/4 of the engines I service are courage singles in Husqvarna tractors .
I love them , just a shame that they changed over to the cast crank mid production which played havock with the balance .

Click to expand...

This made me throw up a little bit.

Sounds like there may be a collapsing fuel line or something in the gas tank blocking the fuel port, causing it to starve for fuel.

ChrisBFRPKY said:

And this. Once you get the engine bolted to the frame, check to make sure your engine has an adequate fuel supply. Check for loose debris in the tank, check to make sure the fuel pump is good and check for pinched off fuel lines. You have an obvious fuel starvation problem. I've read thru the thread and if you've made sure the carb is not the issue by cleaning all fuel passages then the issue is going to be a fuel supply problem.

BTW, the engine video of the one side overheated was caused by running the engine for an extended period without the fan shroud/blower housing. Any air cooled engine will overheat without that shroud/housing in place.

Click to expand...

I was thinking the same thing when i watched the video.
Be sure to check the fuel tanks for water.
Those amoebas of water will slosh around on the bottom of the fuel tanks and give intermittent run issues as it picks it up and digests it.

Try draining the fuel tank and looking at the connection between tank and fuel line. Your symptoms are very similar to mine and I found a debris (mud) plug in the elbow connection to the tank that was essentially allowing 95% of fuel demand so it took about 20 min to drain the carb bowl of fuel and then it would sputter and die. Playing around with the choke would save it for a little bit but would eventually die. Blade engagement puts more demand on engine and therefore burns more fuel and makes it worse. Possibly your air compressor did not dislodge a debris plug like the one I had… something to consider, at least.

Just a thought, although most of my work repairing is on Command series twins. Most suggestions is what Rivets suggested previously. It definitely sounds like a fuel issue to me. It was mentioned previously that the carb was cleaned several times. Did the jets and emulsion tube get cleaned during any of those cleanings? Also, was the fuel solenoid checked and cleaned? Any or all of these can result in lean condition. Also, to completely test the ignition coils, run it with the inline spark testers. Then when it starts running rough check each spark tester. It could be that one coil is failing when hot. Complete lack of power is the result.

I would tend to go after a coil issue, but one other thing you can chek. Sometimes the fuel lines will swell up inside and will look fine from the outside. The same problem occured on the short rubber brake lines on cars. It's not the gas that will break down the rubber on the inside of the hose, but some of the chemical in additives, to clean out fuel systems, will swell the inside of the fuel line restricting fuel flow. However when this happens it usually effects the engine hot or cold. Just a thought though, if you have tried everything else. Cintinue the fight and don't give up!

As far as testing fuel solenoid, it should have been removed for cleaning. The solenoid needle needs a good seal to stop fuel. You can bench test it by disconnecting solenoid wire then using a couple of jumper wires from a 12V source, connect negative source to the solenoid body and the positive source momentarily to the positive lead from the solenoid. The needle should retract when power to connected. If it retracts consistently the solenoid is fine. Use carb cleaner on the solenoid and carb port to ensure any debris or varnish is removed.

MrLarkins said:

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

Click to expand...

Worth checking the exhaust isn't blocked, easiest way is to remove it and try with ear defenders on.

MartinR said:

Worth checking the exhaust isn't blocked, easiest way is to remove it and try with ear defenders on.

Click to expand...

Banana in the tail pipe?

Coils can go out when engine warms up. Check spark or cylinder activity when engine starts acting up. If it cools down coil most likely will start working again.

MrLarkins said:

If I were to sell this mower to another homeowner near me and tell them about the issue, what is a fair asking price in your opinion.

Click to expand...

Tell them it's worn out with 2000 hours on it. You pay them to take it off your hands. Used mowers always have some issue. If they ran good they would never get sold.

Why did you ignore Bert and his comments to you? Your next post was about a fuel filter and went on to something else which didn't work either.

I have not been impressed by the Twin 25 hp "K" engine at all after 4 years. The 25 hp "Briggs" on my 12 year old "Snapper" knock-off is superior across the small engine paradigm.
Also, the easily maintainable "S" Hydro trans has proved to be superior as compared to the impossible to maintain Husqvarna.
Get an Ohm reading on both Coils, bet one is bad.....

MrLarkins said:

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

Click to expand...

I wonder if one of the coils fails when it gets hot. Usually they last for better than two years, but who knows the quality of components these days, or how much use your machine has compared to most. Good luck.

Zue said:

Coils can go out when engine warms up. Check spark or cylinder activity when engine starts acting up. If it cools down coil most likely will start working again.

Click to expand...

I've been reading this post from the beginning, and totally agree on coil theory. I've experienced this mostly on older equipment with high hours on engine, regardless of manuf. As a rule it's a common issue, but coils are unpredictable and can fail at any time. The symptoms indicate a coil, but the excessive fuel and loss of oil indicate your engine may have multiple problems needing attention.

I had this problem with a Kohler engine of the same model, but older. It turned out the compression of one cylinder was low. Easy to fix if you know how to lap the valves..

MrLarkins said:

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

Click to expand...

I would check for timing AFTER I pull the gas filter and run it without the filter for 5 min to check for a difference. Some filters are sensitive to water and if you DID have water in the gas or condensation it could mess it up.

The symptom's first very much sound like a coil . It is puzzling that if you pull choke it helps . Coils aren't that expensive. I try replacing both coils . If no luck try all new fuel line and maybe even go to an electric low psi pump, with a clear in line filter and look at fuel in filter if acts up to see if filter is full of fuel or not.

I can't wade through all seven pages of these posts but did anything ever get resolved?
My first thought is always when some customer says they clean out the carburetor I just roll my eyes because nine times out of 10 or more like 99 times out of 100, they did not clean it properly because most of them don't even know where the jets are located.
So, I would want to get the engine to where it's not running perfectly and then give it a little bit of choke or use a folded shop cloth to restrict the airflow a little bit to see if that smooths it out..
I would also make sure the fuel cap is venting but that probably has an EPA tank anyways but vacuum building up in the fuel tank can cause funny fuel delivery issues.
Then, the most likely beyond all that would be a call getting hot and breaking down.
I've had two of the newer 7000 series lose a coil or have a coil breakdown when hot.
In this case you're going to have to run it until it starts messing up and then put it in a medium speed and run it on each cylinder by pulling the plug wires off one at a time to see if you can tell if one is weak..
Then I would also be putting a new set of plugs in there and looking at the plugs to read them after a few hours mowing.

Then, check the engine mounting bolts because I find a lot of them that are loose in the engine is rocking back and forth or twisting in other words on a start.

MrLarkins said:

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

Click to expand...

Replace the carburetor. Sometimes the check valve can be partially blocked and cleaning wont solve it

MrLarkins said:

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

Click to expand...

The engine

MrLarkins said:

First time poster here, thanks in advance.

I'm running a Husqvarna RZ5426 with a Kohler SV735 (Courage 26hp 725cc). I purchased it new years ago and have maintained it well. This season something has changed. Let me describe the symptoms and tell you what I've looked at already.

Symptoms:

1. Runs a slight bit rougher than normally. By this, I mean that the engine shakes more than years past, but it isn't much.
2. Starts fine and runs for a good 15 mins; Then the engine will wain when under a strain, to the point where it dies. This can be mitigated somewhat by disengaging the blades and releasing the handles so that it idles in neutral.
3. If the engines does shut off, it can easily be restarted, but runs best if let set to cool down.

What I've looked into:

1. I've checked the oil level; it is full but not overfull. Oil is clean from a recent change.
2. There is no smoke in the oil fill pipe as would be the case if a head gasket was leaky.
3. The carb was taken off, apart and cleaned. No trash was in it.
4. Gas is fresh, and fuel filter was replaced last year. Fuel pump was tested and is pumping as it should.
5. Air filter is new for the season and not clogged.
6. Battery is 1 year old and holds at 12.8v.
7. Spark plugs have spark. I did disconnect each spark plug momentarily to see if each cylinder was firing. I did this quickly so the engine wouldn't run too long...just a couple of seconds. Each cylinder ran fine.
8. I cleaned the debris was the engine block fins, thinking it was a cooling issue. one side seems clogged with grass, but there was no oil leaks anywhere on the block, and I looked hard after taking covers off.

The only defect I did find was a crack in the muffler.

Okay, there it is. Any suggestions of what I should look into next?

Click to expand...

The engine, after warming up, may for some reason be running to lean. If there's a carburetor choke, try closing it slightly to see if there's a noticeable improvement. If there's improvent try a higher octane gas. (As long as it won't damage engine).
Just a thought

When the mower starts to die, spray starter fluid in the carb, if the engine starts to run better it’s a fuel issue, if not, I’d go with coil.

Check for craked fuel hoses, coil breaking down under load after it heats up or main jet wells having buildup in them and leaning it out and making it get hot. It can also be any wiring in the ignition system being corroded and breaking down

Tom O' said:

The engine

The engine, after warming up, may for some reason be running to lean. If there's a carburetor choke, try closing it slightly to see if there's a noticeable improvement. If there's improvent try a higher octane gas. (As long as it won't damage engine).
Just a thought

Click to expand...

Exactly! This should be standard troubleshooting procedure when one isn't running correctly. You're either use a folded shop cloth to block off the intake hole at the carb a little bit or close the choke slightly if that's easier to see if it changes the way it runs.
Typically you'll find more engines run lean than rich and if one is running lean it will usually be stumbling a little bit or slowing down due to leaning out.
As soon as you get the joke about halfway to 3/4 way shut you should see it smooth out and speed up if so you know the carb is partially restricted.
Yes before you even get to halfway it starts to burble and chug even more than you know it is running rich and that could be from lack of ignition on a cylinder but regardless this is how you should troubleshoot every running issue.

first pull said:

Replace the carburetor. Sometimes the check valve can be partially blocked and cleaning wont solve it

Click to expand...

I'm a little confused by this term check valve if you use.
I'm not aware of any such part being in any of these carburetors.
They have a needle and seat or what's called an inlet needle or inlet valve etc but those very rarely get clogged up and don't flow.
The vast majority of times when an engine does it run properly and it's from a carburetor issue, it is because the jet, typically the main jet in the carburetor is clogged for slightly restricted.
This is not a check valve situation as it is a fixed orifice jet.

Roost has a Dixie Chopper w a 27 hp Kohler twin, I have to replace a coil every 2 yrs or so. Yours has one, I'd buy one and put it on

Tom O' said:

If there's improvent try a higher octane gas. (As long as it won't damage engine).

Click to expand...

What for?

MrLarkins said:

Starting up <--video link

Mower issue: it dies when warmed up. <--video link

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What isle at your local walmart are new human eyes and ears sold on? And those nearly bare feet while operating an 1800lb mower? No seat belt and no foot grip?

Looks like Larkins checked out several pages ago.

Did you hit a stone or something else while mowing. After you hit something the mower can be out of balance.

Is this the engine with the accelerator pump attached to the carburetor? Symptoms sound similar to my friend’s mower, with carb spewing gas and excessive vibration. Fuel was pooling up at the front of the carburetor causing it to run too rich and shaking the whole engine. I plugged the small tube going from the accelerator pump into the carb, and it totally fixed the problem. Not sure if this carb has those features or not, as I posted about the ”running rich” issue a couple of months ago, and got great advice on the accelerator pump. May or may not be related to this problem.

slomo said:

What isle at your local walmart are new human eyes and ears sold on? And those nearly bare feet while operating an 1800lb mower? No seat belt and no foot grip?

Looks like Larkins checked out several pages ago.

Click to expand...

Still here, still reading and taking suggestions. Not much else I can do though.

mcHarley said:

Did you hit a stone or something else while mowing. After you hit something the mower can be out of balance.

Click to expand...

nope

slomo said:

What isle at your local walmart are new human eyes and ears sold on? And those nearly bare feet while operating an 1800lb mower? No seat belt and no foot grip?

Looks like Larkins checked out several pages ago.

Click to expand...

Uh. Most mowers don't have seat belts and most don't have ROPS either.
Every time I have used a rider or a zero turn like that it has been in short pants and flip flops and I've never worn safety glasses when using any mower.

I've come much closer to having an injury from working on tools, saws, appliances, cars etc even just rust falling into eyes or brake fluid etc then I have ever by operating any mower.

To each their own....I guess.

This is a long shot but I was given a kohler engine on a heavy road equipment bitumen stripper. It presented the same symptoms but after having been serviced. After eliminating valves, plugs, air leaks, fuel age and quantity, I removed the fuel lines and found that an in-line filter had been fitted and was back to front by the directional arrow. I changed it around and the client advised it is now working fine.
Something so simple but easily overlooked by complex diagnostics and thinking. Trust this help.

I had a command 25hp twin.... It had an injection module that was going bad. It behaved the same way. After about 8mins it would stumble then die. Eventually, the module burned up smoking... This was nearly impossible to troubleshoot... eventually replaced the flywheel and ignition coils which eliminated the module. Your coil will have two spade tabs rather than one if you have this setup. And there will be a small electrical box (relay sized).

A second thing I've seen is a plugged air filter (that did not look that dirty) which would cause the engine to stumble after about 15 mins. Swapped air filter all was well.

Your situation sounds like a heat related issue or an issue that just takes time to develop. This can be electrical or mechanical.

Electrical issues (many electrical parts can fail in a way where they heat up, they stop working):
1) connectors where higher current is present (ignition switch, voltage regulator, battery terminals, ground connections)
2) Voltage regulator itself
3) Stator
4) backfire solenoid (on bottom of carb)

Mechanical issues:
1) look at joints (intake to head, intake to carb, hoses to carb etc.)
2) hose ends, look for loose fitting, cracked, dry rot etc.)
3) head to block

The above tend to manifest as spark and air problems.

Fuel Related Problems
1) Carb (you can bypass all other fuel related parts by using a gravity fed tank to see if the problem goes away; if so, the rest of fuel system is ok)
2) Filter
3) Pump
4) Sludge in tank. (can get "sucked" upto filter and prevent flow)
5) Cracks in fuel lines; (in tank, the crack can be below the fuel line and work fine until the fuel level drops)...

Many of these are things that may have been looked at directly or indirectly or seem simple. I don't mean to insult you or anyone else... I hope this will stir others' thoughts for more specific things.

TobyU said:

Uh. Most mowers don't have seat belts and most don't have ROPS either.
Every time I have used a rider or a zero turn like that it has been in short pants and flip flops and I've never worn safety glasses when using any mower.

I've come much closer to having an injury from working on tools, saws, appliances, cars etc even just rust falling into eyes or brake fluid etc then I have ever by operating any mower.

To each their own....I guess.

Click to expand...

Most of us on here are all about safety. Why? Because there is a better alternative. You know, a smarter way of living slash doing things.

When I was a kid my grandfather lost an eye using a weedeater. No glasses worn while using. That was tough to see. I was there when it happened.

Later in life working on a yard crew, couple guys did the same. Oh it's just a small yard and left their safety glasses on the dash. We will just be here for a minute...... And we sat in the Emergency Room all day. One guy was leftie after that. Other was nicknamed RIGHT!!! I would yell it at him RIGHT.

Do as you wish guy. I hope nothing ever happens to you or your family.

Even Superman was not immune.

KGB1a said:

This is a long shot but I was given a kohler engine on a heavy road equipment bitumen stripper. It presented the same symptoms but after having been serviced. After eliminating valves, plugs, air leaks, fuel age and quantity, I removed the fuel lines and found that an in-line filter had been fitted and was back to front by the directional arrow. I changed it around and the client advised it is now working fine.
Something so simple but easily overlooked by complex diagnostics and thinking. Trust this help.

Click to expand...

There was even a factory kohler TSB about fuel filters on the older commands. Using aftermarket filters could cause a problem or after it ran a while it would not flow enough fuel and a factory cooler filter fixed it up.
It's probably the only engine I've ever seen a situation for the fuel filter made any difference at all. Normally you can go 20 plus years on a fuel filter and not even change it and the fuel filters will never be full of fuel but only like a quarter to half full and they will run just fine.

slomo said:

Most of us on here are all about safety. Why? Because there is a better alternative. You know, a smarter way of living slash doing things.

When I was a kid my grandfather lost an eye using a weedeater. No glasses worn while using. That was tough to see. I was there when it happened.

Later in life working on a yard crew, couple guys did the same. Oh it's just a small yard and left their safety glasses on the dash. We will just be here for a minute...... And we sat in the Emergency Room all day. One guy was leftie after that. Other was nicknamed RIGHT!!! I would yell it at him RIGHT.

Do as you wish guy. I hope nothing ever happens to you or your family.

Even Superman was not immune.
View attachment 65595

Click to expand...

You will notice I said nothing about weed eaters. I said lawn mowers and zero turns.

I hate weed eaters and when I use them, which is very, very rarely, I have to wait until I happen to have jeans on because using a weed eater in shorts beat your legs to death with debris and that's just uncomfortable.
It's also very smart to use safety glasses if you don't wear glasses when using a weed eater because those little jerks throw things everywhere..
I have no problem taking My chances with a push mower or sitting on a ride or a zero turn with no safety glasses on and frankly anytime I see someone who put safety glasses on for that I just roll my eyes, yes, I still have two of them, and shake my head.
As I said, to each their own but I do call a lot of people safety freaks.

In fact, for zero turn mowers and commercial grade mowers it's not the operator that should have safety glasses on it's the other people who may be in the vicinity!!

Hea,

Have you replaced the spark plugs or checked them very closely for cracks? I've seen a hairline crack in the ceramic part of the spark plug, start to act up once it gets hot. Also, almost 2k hours on that mower, wow. You've definitely gotten your money out of it, if that's any consolation. Good luck.

I am going to suggest simple....look at your choke linkage and springs...also look at your throttle valve to governor linkage and main spring and damper spring. Sometimes that linkage gets damaged from debris, branches, twigs...and or the springs are missing. Without those linkages and springs the carb could be starving the engine of fuel...as either of those two valves might be erratically uncontrolled. Just a suggestion to rule out something, before you get elbows deep.

MrLarkins said:

I don't have a tool to check compression values, but I can say that there is bounce/kickback when I spin the crank by hand for what its worth. I just checked the oil level after letting the engine cool for an hour and it is 1/2 between E & F. I remember it was Full just a couple days ago, but was also filled with fuel as well (remembering it gushing out the breather tube).

Click to expand...

Buy a compression tester and a leak down tester. These are necessary first steps to diagnosis engine running issues. Everything is just guessing, seem to be getting off course?? Valve adjustment cold (70 degree ish) compression, warmed up engine. Good luck!!

Hey folks, I was away for a few days (29th anniversary celebration), but I'm back today. Mowed when I got home and was able to cut the whole 1.1 acres today(93F) without a single problem. Not even a hint of a problem. I haven't done anything since the last time I tried to mow. Go figure.

MrLarkins said:

Hey folks, I was away for a few days (29th anniversary celebration), but I'm back today. Mowed when I got home and was able to cut the whole 1.1 acres today(93F) without a single problem. Not even a hint of a problem. I haven't done anything since the last time I tried to mow. Go figure.

Click to expand...

Sometimes it just happens that way. Thanks for the update.

STEVES said:

Buy a compression tester and a leak down tester. These are necessary first steps to diagnosis engine running issues. Everything is just guessing, seem to be getting off course?? Valve adjustment cold (70 degree ish) compression, warmed up engine. Good luck!!

Click to expand...

I can't agree with that.
I have worked on thousands upon thousands of engines and the last time I screwed a compression tester into a lawn mower engine was probably when I was about 12 years old when I first got a compression tester because that was the closest most convenient thing to make the needle go up.

Now I'll leak down tester could be more valuable but actually just using compressed air and blowing into the cylinder with an adapter would be probably better than I leak down tester..
A compression tester is such a moot point on a lot more engine as most of them have acr's etc and you're not going to get anywhere near an accurate reading to tell you anything and in reality they basically either have plenty of compression or they have almost none.
Simply putting your thumb or finger in the hole and pulling the rope or spinning the blade is more than enough to tell you anything you need to know.
It's irrelevant what the actual number is on the meter so I stopped using the compression tester for mowers decades ago..

TobyU said:

and pulling the rope or spinning the blade is more than enough to tell you anything you need to know.

Click to expand...

Agreed. No need for NASCAR tools on lawn mowers.

slomo said:

Agreed. No need for NASCAR tools on lawn mowers.

Click to expand...

As Greta would say
"HOW DARE YOU!"

Had a generator with low compression, started ok, but bogged down with load applied. Compression test told story, no need to go any further, like Oh NO must be carburetor. So yes, there is need for basic testing, especially since I have a 'not so smart thumb pressure gauge'! Spin over 500-600 rpm to by pass ACR.

STEVES said:

Had a generator with low compression, started ok, but bogged down with load applied. Compression test told story, no need to go any further, like Oh NO must be carburetor. So yes, there is need for basic testing, especially since I have a 'not so smart thumb pressure gauge'! Spin over 500-600 rpm to by pass ACR.

Click to expand...

That sounds like a lot of work and kind of hard to tell if you're spinning over 500 600 rp.m. or not. You certainly can't use a vibratach for that and the lost all the digital ones I have and have used don't update quickly enough to give you a consistent reading at that low of an RPM and I doubt most of them with the compression from the tester screwed in would even hit that many RPMs but then again I'm also talking about push mowers without electric start that you pull the rope on cuz we all know that the battery powered starter on these little engines but they walk behind mower doesn't spend them anywhere near 500 rpms. It barely spends them enough to start they're so anemic.
I guess I have a very smart phone because my thumb or finger in the hole will tell me everything I need to know about whether it has enough compression to run well or not.
I have done literally thousands of them though so you get a good feel for it.

I guess it's like using a code scanner for a car which is one of the best diagnostic tools available on cars since 96 because it works excellent and tells you exactly where to start.
But I don't need that. If a car has ignition cylinder mess I don't need to plug the scanner in to tell that it has a miss or even tell which cylinder it is. I can simply reach with my fingers and pop off a coil wire or two or injector wire whichever is easiest to cancel out the cylinders until I find the one.
So I see the compression test somewhere to this. But in my case for the lawn mowers it's faster just to see if it blows out the whole hard enough than it is to screw in the tester.

Most on this site looking for help, won't have 'that' feel, price of tester cheaper (usually) than throwing parts at machine. 50 - 60 lbs good considering ACR and under 500rpm. He can always loan to friends & neighbors that may need help. Getting over 500rpm can be done with drill, but, you have to lift off before you let go of trigger, or most time nut will come off! This takes some experience. Leak down tester is for more experienced person, different ways to lock crankshaft so as not to get hurt, or remove rockers. But cylinders wear more at the top for checking ring leakage. Valves or head gasket doesn't matter as much. We all have our way!

STEVES said:

Most on this site looking for help, won't have 'that' feel, price of tester cheaper (usually) than throwing parts at machine. 50 - 60 lbs good considering ACR and under 500rpm. He can always loan to friends & neighbors that may need help. Getting over 500rpm can be done with drill, but, you have to lift off before you let go of trigger, or most time nut will come off! This takes some experience. Leak down tester is for more experienced person, different ways to lock crankshaft so as not to get hurt, or remove rockers. But cylinders wear more at the top for checking ring leakage. Valves or head gasket doesn't matter as much. We all have our way!

Click to expand...

Well, if someone doesn't have the feel for compression blowing out of the hole in their finger they certainly aren't going to have the ability to remove the shroud and adapt it with a drill chuck and an adapter to fit a socket so they can spend one over and as I said from the beginning it's just more work than most people need to deal with or that's even necessary.

I have guided pure novices and homeowners through that basic test over the phone many times.
It's not an experienced or educated feel that someone needs.
It's simply the fact that it blows your finger out of the hole when someone else pulls the rope or when they crank the engine over if it's a starter on a rider.
In fact, sometimes it's just a matter of seeing if the piston is going up and down.
Just had one the day before yesterday or maybe it was yesterday call me about a twin that he knew was low on oil and it made some sort of noise and now won't run but it does still spin over without any noticeable noise.
For the first basic diagnosis, the actual amount of compression is quite irrelevant but rather seeing that it has anything from both pistons moving up and down is what's important.

Also, with the finger test regardless of the pressure I explained to people how it should blow blow blow blow blow.
It should be very rhythmic and in a pattern and never have like double blow and then a space and then double blow and it should never try to suck your finger into the hole.

These two tell you you have valve issues, normally with one not opening.
Or, if you have not enough pressure to even blow your finger out of the hole you could have a valve staying completely open like a popped valve seat etc.

All of this can easily be diagnosed but ever actually knowing whether or not you have good full compression or only 85% compression.
I use percentages because again it's kind of irrelevant what the actual number is on the compression tester but more important what it normally is on decent running engines on that same compression tester.
I just hate to see people go out some number and often when people use a compression tester they're expecting at least 100 if not 120 to 150 like on a car.
So when they don't get that because of the acrs they often start thinking of other things that are damaged or tearing into things and causing other problems and expense when all of that was perfectly fine and it was something else to begin with but their numeric number on a compression tester led them down the wrong path because they didn't really understand the situation.
It's fine if someone has done lots of engines and expects to only see 70 on the compression tester but the average person dabbling into this or auto mechanic will not come to this conclusion quickly.

You're right, everyone has their own methods and ways and I somehow once I started doing this morphed and evolved into the absolute most efficient, minimalist way to do everything and then get on to the next one.
Not in a reduced quality sort of way either because my shops reputation for quality work and doing little extra for people speaks for itself and all of the reviews.
I just seem to find all the little tricks and ways to do things quickly and efficiently even if it is a little bit harder for the short period of time I'm doing the work.

You can take a row of other people and myself and present us all with an identical situation mower and say get it running or fix it whatever.

You might find me hanging from a harness from the ceiling basically standing on my head with a head spotlight on and a mirror etc but I would be done in a short number of minutes.
Everyone else would probably have just barely disassembled something and have it over on there very convenient and easy to work on workbench going through something and then they would have to go back and reassemble it all taking 35 to 50 minutes etc when I was done in 9.
I will admit speed isn't everything and it's not good at sacrifices quality but that's not the case with me.
I just choose to work a little harder for a shorter period of time.
Time is of the essence in two situations that I can think of in this regard.
When you have a whole lot more to get to after you finish the one you're on or when you actually work very little so when you do get around to working you have to get a lot done for every minute you work. Lol