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JD- ZtrackZ425

#1

M

macdoesit

Bought new in 2010. one cylinder is dead. I took the ignition coil and sparkplug and switched them around, the good cylinder fired but the dead cylinder is still dead.
Can anyone tell me what the problem is??
Thank you


#2

ILENGINE

ILENGINE

Remove the spark plug and turn the engine over slowly by hand and see if that piston is going up and down. Remove the valve covers and see if the push rods are still in place and not fallen out.


#3

M

macdoesit

ILENGINE said:
Remove the spark plug and turn the engine over slowly by hand and see if that piston is going up and down. Remove the valve covers and see if the push rods are still in place and not fallen out.
Click to expand...
If that was the case, wouldn't it make a loud knocking noise while running. It does run but only on one cylinder.
I did take the spark plug out and started it and air came out of the cylinder.


#4

ILENGINE

ILENGINE

It may not knock even if one rod is broke. And a missing push rod will prevent it from running on that cylinder. Intake push rod won't normally cause a popping noise. Sometimes the exhaust valve push rod missing can cause a popping back through the intake, but not always.


#5

M

macdoesit

ILENGINE said:
It may not knock even if one rod is broke. And a missing push rod will prevent it from running on that cylinder. Intake push rod won't normally cause a popping noise. Sometimes the exhaust valve push rod missing can cause a popping back through the intake, but not always.
Click to expand...
Compression is at 88 and no bleed off


#6

StarTech

StarTech

1749682715679.png

These Briggs engines uses a two piece intake manifold that is fused together. They do split sometimes causing problems.


#7

Tiger Small Engine

Tiger Small Engine

macdoesit said:
Compression is at 88 and no bleed off
Click to expand...
Remove valve cover, as previously stated, and look at intake and exhaust valves. Are push rods in place and not bent? Are the springs moving freely and equally? 88 psi compression is on the low end. Is that reading from the cylinder that is not firing?


#8

A

Auto Doc's

Disconnect the coil kill wire on each coil and see if the engine now runs on both cylinders. The engine can be shut down by the after-fire solenoid on the carburetor, when the key is turned off.

If it does run fine disconnected, the kill wire harness has a bad inline diode for one of the coils.

Use the numbers stamped into the top of one of the valve covers to look for parts. Parts Tree, Ereplacement.com or Jack's small engine should show the kill wire harness but be careful of which one you have, because they had a couple of different ones.


#9

M

macdoesit

Took valve cover off. one exhaust and intake pushrods, one was laying under rocker arm broke, the other I assume is in the bottom of the engine. I ordered both rods, both valve tappets. Is there anything else I need to order?
Can rods be replaced without breaking down the engine?IMG_20250612_133536492.jpg

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#10

M

macdoesit

Bought a new 54inch cut JD yesterday. These new ones ride like Cadillacs, and cost about the same. LOLIMG_20250611_115650811.jpg

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#11

ILENGINE

ILENGINE

macdoesit said:
Took valve cover off. one exhaust and intake pushrods, one was laying under rocker arm broke, the other I assume is in the bottom of the engine. I ordered both rods, both valve tappets. Is there anything else I need to order?
Can rods be replaced without breaking down the engine?View attachment 71102
Click to expand...
If one of the push rods is down in the engine sump. the bottom of the engine will need to be removed to retrieve the push rod and/or parts before they cause more damage. I have seen push rods get wrapped around the cam and break the compression release. You will need the crankshaft seal and the sump gasket kit.


#12

A

Auto Doc's

No shortcuts here. Pull the engine and get the loose parts out. Hopefully there is no internal damage. If you are not a mechanic, this is not a time to start trying to be one. Maybe looking around for an independent small engine repair shop would be best. I don't suggest the dealer because they cost much more and seldom have people that are formally trained in this kind of repair. Dealers typically hire people only for new equipment setup and oil changes along with minor maintenance.

This damage tells me that a valve guide has moved up in that head due to repeated overheating. When this happens, the rocker cannot fully open the valve, then the push rod is sacrificed. In a worst-case scenario, it could break the camshaft and ruin the inside of the engine.

The head will need to be replaced if the valve guides have moved. No... Driving the guides back down in place will not fix the issue.

Teryl fixes all has a video about drilling and using a set screw to hold the problem valve guide, but that will take a lot of working knowledge and special tools to accomplish.

Option 2: Look at getting a new or lightly used zero turn but stay away from any that have "intelligent" electronics or lots of bells and whistles. New mowers are getting loaded down with lots of electronic failures.


#13

StarTech

StarTech

Please be aware the 594195 gasket [which includes bolts] have had problem the new gaskets blowing in past; unless, Briggs has fix the gasket paper quality problem.

I had three to blow on the same engine within a month. They look like Swiss cheese when I disassemble the engine. I got some aftermarket gaskets out CA and they are still holding two years later. They felt a lot better before I install the new gasket.


#14

M

MParr

Auto Doc's said:
No shortcuts here. Pull the engine and get the loose parts out. Hopefully there is no internal damage. If you are not a mechanic, this is not a time to start trying to be one. Maybe looking around for an independent small engine repair shop would be best. I don't suggest the dealer because they cost much more and seldom have people that are formally trained in this kind of repair. Dealers typically hire people only for new equipment setup and oil changes along with minor maintenance.

This damage tells me that a valve guide has moved up in that head due to repeated overheating. When this happens, the rocker cannot fully open the valve, then the push rod is sacrificed. In a worst-case scenario, it could break the camshaft and ruin the inside of the engine.

The head will need to be replaced if the valve guides have moved. No... Driving the guides back down in place will not fix the issue.

Teryl fixes all has a video about drilling and using a set screw to hold the problem valve guide, but that will take a lot of working knowledge and special tools to accomplish.

Option 2: Look at getting a new or lightly used zero turn but stay away from any that have "intelligent" electronics or lots of bells and whistles. New mowers are getting loaded down with lots of electronic failures.
Click to expand...
This time of year dealer repair shops are swamped. Some will push warranty repairs and commercial clients to the head of the line. There could be up to a three week wait. I would suggest an independent repair shop.


#15

StarTech

StarTech

MParr said:
This time of year dealer repair shops are swamped. Some will push warranty repairs and commercial clients to the head of the line. There could be up to a three week wait. I would suggest an independent repair shop.
Click to expand...
And if an independent shop can look at it, the time frame for completion depends on if they have all the parts in stock. If not that will throw a delay in completion of the repairs. Small shop like mine cant keep every rarely used part in stock.

I am currently working on a JD side by side. It been in the shop over a month awaiting a carburetor mixture screw that customer's son broke off. All the other parts got here in two days.


#16

A

Auto Doc's

Hello Star Tech,

The variety of equipment has become so vast that I stock very few parts on hand. The old days of common stock parts have passed. I get what I can local, but a majority of my parts are ordered online these days. Even the dealers have reduced their parts stock tremendously. In your case it would have been easier to get a complete (expensive carburetor) then a simple mixture screw.

If a customer expects same day for any in depth repairs, it's just not going to happen. I explain the situation up front and if they are in a rush, maybe they will have better luck somewhere else, but that is seldom that works out for them.

As a good automotive mechanic friend of mine says quite often: "I did not buy it, build it or break it, all I can do is fix the machine if allowed the proper time needed".

A self-entitled customer throwing a tantrum or tapping their foot impatiently while surfing their phone does not phase me these days. If they get belligerent, that ends all conversation immediately. I do not suffer fools well.

Dealers this time of year are swamped to a point where they often turn customers away unless the machine was purchased from them. Even then it may be a 2-3 week wait (or longer) before it is even brought in for evaluation.

Most independents in my area have folded because it has become so hectic and they are just fed up. Poor quality parts from the aftermarket and even the dealers have become a huge problem post COVID era. When it takes a couple of times to finally get a good part, all profit is lost.

Years ago, when I was a service manager at a JD dealer, I would cringe every time a (fun) 3rd party extended warranty job would come in because the warranty company wanted to dictate the repair terms and cut corners.

I hated to do it, but those kinds of jobs typically got moved to the back of the line because they took so long to negotiate terms and get approvals for repairs. It really hit the fan when the customer expected repairs to be fully covered... Often time the customer had to pay a deductible or the difference in cost of the repairs. Of course, they never read the contract.


#17

Tiger Small Engine

Tiger Small Engine

Auto Doc's said:
Hello Star Tech,

The variety of equipment has become so vast that I stock very few parts on hand. The old days of common stock parts have passed. I get what I can local, but a majority of my parts are ordered online these days. Even the dealers have reduced their parts stock tremendously. In your case it would have been easier to get a complete (expensive carburetor) then a simple mixture screw.

If a customer expects same day for any in depth repairs, it's just not going to happen. I explain the situation up front and if they are in a rush, maybe they will have better luck somewhere else, but that is seldom that works out for them.

As a good automotive mechanic friend of mine says quite often: "I did not buy it, build it or break it, all I can do is fix the machine if allowed the proper time needed".

A self-entitled customer throwing a tantrum or tapping their foot impatiently while surfing their phone does not phase me these days. If they get belligerent, that ends all conversation immediately. I do not suffer fools well.

Dealers this time of year are swamped to a point where they often turn customers away unless the machine was purchased from them. Even then it may be a 2-3 week wait (or longer) before it is even brought in for evaluation.

Most independents in my area have folded because it has become so hectic and they are just fed up. Poor quality parts from the aftermarket and even the dealers have become a huge problem post COVID era. When it takes a couple of times to finally get a good part, all profit is lost.

Years ago, when I was a service manager at a JD dealer, I would cringe every time a (fun) 3rd party extended warranty job would come in because the warranty company wanted to dictate the repair terms and cut corners.

I hated to do it, but those kinds of jobs typically got moved to the back of the line because they took so long to negotiate terms and get approvals for repairs. It really hit the fan when the customer expected repairs to be fully covered... Often time the customer had to pay a deductible or the difference in cost of the repairs. Of course, they never read the contract.
Click to expand...
It has been very busy for me for last 2-3 months. I am up to 3 weeks out on service and repairs. When a customer calls and their first question is “how far out are you on repairs?”, I know they will usually keep calling shops, and that is fine.
To be able to keep anything except the basic parts in stock I use (don’t sell parts), is pointless. I order as needed mainly online.


#18

StarTech

StarTech

Tiger Small Engine said:
To be able to keep anything except the basic parts in stock I use (don’t sell parts), is pointless. I order as needed mainly online.
Click to expand...
I agree there. I do have over $100,000 in inventory and most of it seldom moves. Still having to buy a lot of parts from the distributors. One good thing most parts are only two days out. Even with two distributors of OEM parts I find myself ordering from someone online at times.

I had one customer that didn't want to wait two days for a hex belt and found a competitor that is closing down that had it. That guy took a hit on the profit margin for belt. but at least he made a profit. Still took an hour to put it on but he got bill for the time and he was happy to pay the bill as he saw what i had go thru to put the belt on. Boy a JD 445 deck belt is fun to on, Not. At least I did it under a shade tree on the driveway.


#19

ILENGINE

ILENGINE

StarTech said:
I agree there. I do have over $100,000 in inventory and most of it seldom moves. Still having to buy a lot of parts from the distributors. One good thing most parts are only two days out. Even with two distributors of OEM parts I find myself ordering from someone online at times.

I had one customer that didn't want to wait two days for a hex belt and found a competitor that is closing down that had it. That guy took a hit on the profit margin for belt. but at least he made a profit. Still took an hour to put it on but he got bill for the time and he was happy to pay the bill as he saw what i had go thru to put the belt on. Boy a JD 445 deck belt is fun to on, Not. At least I did it under a shade tree on the driveway.
Click to expand...
I would rather replace the belt on the 445 deck than replace the belt on the JD freedom deck.


#20

M

macdoesit

I willhttps://www.lawnmowerforum.com/attachments/img_20250611_115650811-jpg.71109/ just use it for parts or buy a new engine for 1,400.00 and keep it as a backup mower.IMG_20250611_115650811.jpg


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