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So a few months back, I posted saying that my L110 would barely crank. That problem was easily solved with a new battery.

Now the bigger problem: It will crank all day, but not start. Last fall it had a tune up, and ran as of October.

A few observations of what's going on:

1) The spark plug is firing, and is new as of the tune up at the end of last mowing season.
2) The tank is full of treated fuel, filled a few months ago.
3) When cranking, I smell no fuel. I also smelled no fuel when I pulled the spark plug to check its condition.
4) The yellow bulb with the little filter in it is about 20% full of fuel. When I crank it, no fuel seems to enter or leave.

I fear that fuel isn't making it into the cylinder...actually, I'm almost certain of it.

This lawn mower was incredibly dirty when I inherited it last year. While I did clean it up and have all filters changed, I'm worried that something is clogged. I'm also worried that what ever is pumping or drawing the fuel has broken while the mower sat over the winter.

Any thoughts would be greatly appreciated.

Thanks!

I would pull the carb and thoroughly clean it. I would also dump that old treated fuel for fresh gas. You only want to use gas 30 days old or less. Your car can handle older fuel. Small engines its harder on them. If you spray carb cleaner into the carb will the engine start? I think you will find that even thought the gas is treated its poor quality fuel and plugged up the carb. Post engine model info here and we'll go through the steps to R/R the carb

ndutil86 said:

So a few months back, I posted saying that my L110 would barely crank. That problem was easily solved with a new battery.

Now the bigger problem: It will crank all day, but not start. Last fall it had a tune up, and ran as of October.

A few observations of what's going on:

1) The spark plug is firing, and is new as of the tune up at the end of last mowing season.
2) The tank is full of treated fuel, filled a few months ago.
3) When cranking, I smell no fuel. I also smelled no fuel when I pulled the spark plug to check its condition.
4) The yellow bulb with the little filter in it is about 20% full of fuel. When I crank it, no fuel seems to enter or leave.

I fear that fuel isn't making it into the cylinder...actually, I'm almost certain of it.

This lawn mower was incredibly dirty when I inherited it last year. While I did clean it up and have all filters changed, I'm worried that something is clogged. I'm also worried that what ever is pumping or drawing the fuel has broken while the mower sat over the winter.

Any thoughts would be greatly appreciated.

Thanks!

Click to expand...

Thank you for the response!

It's a Kohler CV491S 17.5hp Engine.

Also, I should have mentioned this earlier, as it may help with a diagnosis:

Last fall, the mower was initially brought in for service because it had accidentally been filled with diesel fuel by the previous owner. When it was serviced, the tank was emptied, filters changed, and spark plug changed. After bring serviced, it ran (although a bit rough). That was 7 months ago.

Could the diesel fuel have damaged the carburetor?

Just to update:

I took the air filter housing off (cleaned it all up in the sink and let it dry (air filter is brand new)), removed the solenoid from the bottom of the carburetor, checked to make sure that it was clean, moving freely, and functioning (it was), removed the bowl at the bottom of the carb, checked to make sure that the bulb is freely moving (it is). Throttle cable opens and closes the carb as it should. The outside of the carburetor body was dirty ("was"...it's clean now). The inside was basically spotless. Even the bulb where fuel floats was spotless.

I hit all visible parts with gun bore solvent...not as harsh as carb cleaner, but better than nothing. I then blasted everything with compressed air. I was going to take the whole carburetor apart, but for the life of me I couldn't figure out how to remove it from the engine body. ...there must be something else holding it on.

Anyway, I put it back together, tried starting, and nothing. Actually, I take that back. It burned the solvent that I sprayed into the engine, so I got one quiet fire...at least we know the plug is firing properly.
But, no fuel is making it to the carburetor. Even if fuel flow was poor, there should have been some fuel in the bottom of that bowl that I removed...there was nothing.

Could the jets of the carb be clogged from old fuel? Sure. Should the carb be rebuilt at some point? Probably. But, is it the reason that it won't run at all? I don't think so...

I wanted to remove the fuel line from the carb and try to start it, seeing if the pump will even move the fuel...but I couldn't get that line off no matter what I did.

So, now I'm ordering the potential issues like this:

1) Bad Fuel Pump
2) Clogged Fuel Line
3) Clogged Carburetor Jets

I just ordered a fuel pump, and will hopefully have it in a week.

In the mean time, I'll remove the old fuel from the tank.

Does anyone have any advice on removing the fuel line from the pump (and possibly one day from the carburetor)? These lines don't come off very easily (probably a good thing), and I don't want to break anything while trying to remove them.

Thanks

Removal
Disconnect the fuel lines from the inlet and outlet
fittings of the pump.

EngineMan,

Thanks for the diagram Any advice on how to remove fuel lines that have sort of become "stuck" to the fittings over the past 10 years? I really don't want to damage the lines...

Remove pump from engine with lines on, leave in hot water for a few minutes, then pull apart, well that's the way I have done it in the past..!, you can always fit new fuel lines.

Its always cheaper and better to replace fuel line then try and save them and ruin carb inlet fittings, fuel pump fittings, gas tank fittings. Remove clamps, and cut small slit in the full line where it meets the fittings. Remove. Purchase 1/4" non fuel injection fuel lines. The fuel injection hose is 4 bucks plus a foot. the fuel pump, and gravity feed mowers are low pressure. Go to the auto parts store and purchase 4 feet. That will give you plenty to replace and have extra. Just ask for 1/4" fuel line get the black stuff, not the clear.

ndutil86 said:

EngineMan,

Thanks for the diagram Any advice on how to remove fuel lines that have sort of become "stuck" to the fittings over the past 10 years? I really don't want to damage the lines...

Click to expand...

Sounds like a duff fuel pump.

Thanks for all of the advice! I'm going to drain the tank, replace the line, replace the pump, and put fresh gas in it.

I'll let you all know what happens!

While I'm at it and in the mode of replacing hoses: I'd like to replace the hose that runs from the engine to the air filter housing. It's about 7" long, and about 3/4" in diameter...

Is anyone familiar with this part?

Its the crankcase breather. If its not cracked leave it alone. If looks bad. Replace.

ndutil86 said:

While I'm at it and in the mode of replacing hoses: I'd like to replace the hose that runs from the engine to the air filter housing. It's about 7" long, and about 3/4" in diameter...

Is anyone familiar with this part?

Click to expand...

The breather tube itself isn't cracked, but the tip is becoming slightly cracked. It's beyond the clamp, so I'm not too worried. I'll let it be for now and keep an eye on it in the future.

I am in nearly the exact same same scenario with the exact same mower and engine. I adopted it from my dad's farm and last summer was my first time using it. The battery was dead and I had to boost it everytime but it seemed to take more cranking to get started as the season wore on. Right at the end of the season a tree branch hit the throttle down and turned the mower off, and ever since then I had not been able to start it. I bought a new battery and it will crank like crazy but thats it. Winter set in and I didn't work on it but now I gotta get it running ASAP!

I read somewhere that a stripped flywheel key could cause this so I pulled that all apart but the key seemed intact.

Sparkplug looked questionable so I just outright replaced it,, no help.

Cleaned out carb, was a little dirty but not too bad. The bowl refilled with fuel so I *think* that means the fuel pump is running ok?

It got late so I called it a night but right now my main culprit is the solenoid cutoff valve in the bottom of the carb bowl. I tried getting this thing to run on the bench by just applying voltage but doesn't do anything. I even hooked up a current meter but it draws nothing so I think it has failed open. When morning comes I am going to literally cut off the solenoid plunger to bypass the fuel cutoff. This means the engine will no longer have anti-backfire, not sure how bad that is, but based on some googling I think you can get away with it.

Well I did the solenoid mod and the engine actually started! But, 2 seconds later started getting very loud pops and smoke coming out of the air filter. Seems like some combustion is taking place in the carb now, not sure where to go from here...

travis7s said:

Well I did the solenoid mod and the engine actually started! But, 2 seconds later started getting very loud pops and smoke coming out of the air filter. Seems like some combustion is taking place in the carb now, not sure where to go from here...

Click to expand...

Check the valves are seating, do a compression test. look for a inlet valve staying open.

Two things:

First: To update my situation - The new fuel pump solved the problem. Replaced the pump and fuel line, and gas started flowing wonderfully. As of now, the mower is working just as it should.


Travis, as for your situation: You may need a carb kit to essentially rebuild the carburetor. I think they can be purchased for under $10, and just contain gaskets/jets/other small parts.

Modding the solenoid shouldn't create backfiring while the engine is running...at least I don't think it should. When the solenoid isn't functioning properly, you'll get a backfire inside the carb when the engines shuts off and fuel is still flowing into the carb.

The most common reason for backfiring, from what I have learned through reading about this mower, is a problem with the flywheel - mainly the key. You said that it looked normal, but if something is wrong with how that wheel is functioning, you will get the exact same symptoms as you're describing.

Another thing to note regarding this Kohler 17.5 engine: Buy a more powerful battery than you think you'll need. Originally, the previous owner of this mower tried to get away with a battery rated for a 14hp engine. It had a horrible time cranking. I just dropped in a battery rated for 19hp engines, and it cranks just fine, but might even do better on an even bigger lawn battery.

I'll try taking a look at the valves today, no experience with the inner working of an engine before so that should be interesting.

I'll also take a closer look at the flywheel, maybe I missed something before, it was quite a few months ago that I had it off.

Also if it helps anyone I found a great service manual for very similar Kohler engines:

http://www.asberry.net/files/TP-2339-D.pdf

Well now I feel kinda dumb. Sure enough, when I pull the flywheel off, the key is completely sheared in half! Need to figure out where to get one and then try again...

Don't feel dumb...I can't count how many times I've looked at something and ended up coming back to it to determine that it was the problem

As for the key: Flywheel Key X-42-15-S Order now for same day shipping. 365 day return policy. RepairClinic.com I'm 99% sure that this is the one that you're looking for. I did a search for the CV491 Key (If you have the same Kohler 17.5 engine that I have), and this is what I came up with. (Sears confirms it here: http://www.searspartsdirect.com/par.../Model-CV49127502/0598/1503500/P0050360/00004 )

Repair Clinic also has a video on replacing it, but it looks like you've learned your way around that flywheel (video here: https://www.youtube.com/watch?v=gfoIJHj6MzM )

I hope that solves your problems! It's about as cheap of a fix as you can get.

ndutil86 said:

Don't feel dumb...I can't count how many times I've looked at something and ended up coming back to it to determine that it was the problem

As for the key: Flywheel Key X-42-15-S Order now for same day shipping. 365 day return policy. RepairClinic.com I'm 99% sure that this is the one that you're looking for. I did a search for the CV491 Key (If you have the same Kohler 17.5 engine that I have), and this is what I came up with. (Sears confirms it here: http://www.searspartsdirect.com/par.../Model-CV49127502/0598/1503500/P0050360/00004 )

Repair Clinic also has a video on replacing it, but it looks like you've learned your way around that flywheel (video here: https://www.youtube.com/watch?v=gfoIJHj6MzM )

I hope that solves your problems! It's about as cheap of a fix as you can get.

Click to expand...

Thanks, pretty sure any standard woodruff key thats the same size will work, cheap from McMaster but you gotta buy a pack of 100!

McMaster-Carr

Couldn't wait so I just used a square piece of keystock as a temp fix... now it fires up quick and sounds good! There seems to be a lot of smoke coming off the front end but I think/hope this is because I spilled oil all over that area when I pulled the valve cover off. (didn't drain oil prior, oops) Need to pump up the tires and reassemble so I can take it outside for a real test.

Ive fixed 2 LA series this summer already with the same symptoms. Both were due to the gas cap vent being plugged. Dang mud wasps.

Frog