Craftsman Lawn Tractor problem

[jim]

The lady down the street was moving away and asked me if i wanted to buy her 18 HP Craftsman with a Kohler engine lawn tractor with auto trans and electric start. She said it runs great. Got it home and did the maintenance on it like clean the air filter and oiled the foam liner, changed spark plug and oil, sharpened blade. Starts right up and runs great for the first half hour then it starts to run rough and then it dies. It can be restarted and it will run good for a short time the it starts running rough again. Any suggestions on why it runs great for about half hour and then runs rough after that. It has fresh gas. Thanks

 

[jjkrjh]

I have had 2 tractors that did this. If the tank is kept full they run fine. Possibly a vapor lock issue. When they would start to act up, I would play with the throttle(choking) it to limp back and fill the tank. The tanks weren't low enough to be running out. I was so happy when they went down the road.

 

[tallgrass1951]

I would replace the fuel filter.

 

[manwithtools]

I had a similar problem on a diesel mower a few years ago. Turned out it was the rubber fuel line collapsing on itself after it ran long enough to get warm. Not sure if your problem could be at all similar, but it's cheap to replace the line as a diagnostic.

 

[LB-1911]

The lady down the street was moving away and asked me if i wanted to buy her 18 HP Craftsman with a Kohler engine lawn tractor with auto trans and electric start. She said it runs great. Got it home and did the maintenance on it like clean the air filter and oiled the foam liner, changed spark plug and oil, sharpened blade. Starts right up and runs great for the first half hour then it starts to run rough and then it dies. It can be restarted and it will run good for a short time the it starts running rough again. Any suggestions on why it runs great for about half hour and then runs rough after that. It has fresh gas. Thanks

When it starts to run rough loosen the gas cap and let us know what happens.

 

[dadsEH]

Is it throwing any codes????

 

[PelicanPines]

Does adjusting the choke help?

 

[58Yeoman]

What LB said. I had a JD that did that. The vent hole in the gas cap was plugged.

 

[kbs2244]

Another vote for a plugged gas cap vent.

 

[James-W]

Another vote for a plugged gas cap vent.

Over the years I have found that to be a fairly common problem.

 

[243]

It would help to know what model.

I have an older Craftsman with a Kohler Magnum 18, it had the symptoms stated above and it was the magneto.

I went through all the other diagnostics including rebuilding the carb, fuel lines, fuel filter, cap vent, plugs.

 

[ovilla]

You have a bad ignition coil. I have a JD STX38 with a 12HP Koehler motor. Mine had the same symptoms until I replaced the ignition coil (that's the assembly that is bolted next to the flywheel and has the long spark plug wire that connects to your spark plug). When ignition coils get old and worn they get sensitive to heat and stop working. That's why your mower always starts after its cooled down a bit. When you install the new ignition coil, there's no need for a feeler gauge, just put a business card between the flywheel and the new ignition coil and then tighten the two bolts holding the coil in place.

 

[pstnbly]

I 2nd on the coil.

 

[lakeroadster]

Another vote that the coil is bad. Had similar experience on my JD 265.

 

[LS6 Tommy]

If loosening the gas cap doesn't change anything, my money is on the coil, too

Tommy

 

[jim]

Model # is 917.273160 if that helps. 18 HP kohler. Is the coil and the magneto the same thing? Tried a LITTLE choke and kept it running for a short time before it died. Jim

 

[LS6 Tommy]

Is the coil and the magneto the same thing? Jim

Yup.

 

[SuperCheyenne]

Is it throwing any codes????

Autozone will read the codes for free! Drive it on down there and let them plug it in.

I'm anxious to hear what codes it throws.
I'm betting on
010011000100111101001100


Edit: my post is tongue in cheek. It's probably "not cool" for a noobie to crack a joke. So don't take my post serious.

 

[VocaTexas]

My Craftsman has a Kohler engine and does the same thing. On mine it IS a fuel delivery problem. Keep the tank over half full and it never acts up.

 

[LB-1911]

Model # is 917.273160 if that helps. 18 HP kohler. Is the coil and the magneto the same thing? Tried a LITTLE choke and kept it running for a short time before it died. Jim

Have you checked for spark right after it dies?

Shop the part number, you'll notice a wide price spread - try to stay OEM or an aftermarket with a positive track record.

IGNITION/ELECTRICAL Diagram and Parts List for KOHLER All-Products-Parts model # CV492-27506
http://www.searspartsdirect.com/model-part/cv49227506/0598/1503500/p0302087/00004.html

If loosening the gas cap doesn't change anything, my money is on the coil, too

Tommy

^
That is where I was heading if he reported back that it didn't have any effect.

 

[94EG8]

Kohler Command with the upside down oil filter? I've seen them do what yours is doing if the fuel line is laying on the oil filter. If this is the case tie it up out of the way and try it, if the problem doesn't go away it's more than likely a bad ignition coil. A plugged gas cap will make it shut off after a period of time as well, but it tends to be more in the 15 - 20 minute range, it is worth checking though before throwing a coil at it.

 

[Spareparts]

If it has the vacumn fuel pump make sure the vent screen isn't plugged, it's a small brass colored screen on the face of the pump. A old tooth brush will clean it up and not harm the screen like metal brushes do.

 

[truckman5000]

I had the same problem. Same mower, did the coil and gas system to no help.
It was the valve lash...you know the manufacture says to adjust after the 1st 60 hours or something like that

 

[jives]

I just replaced the ignition coil on my Magnum 20. . . with a coil from a M18. They attach directly to the flywheel, not the canister style with the high voltage wire. iHad to remove the engine to do so on my Simplicity Sunstar. While I was at it I replaced the front and rear oil seal. The point? Check all the gas line issues first.

 

[jim]

Thanks for all the input. Thought I would try the simple things first. Bought a new gas cap but it has been too dry and the grass is not growing. Hope to try it in the next few days.

 

[SIX225]

While researching other issues with mine years ago, I think that there might have been valve lash issues with certain Kohler engines. Something else to check into.

 

[jim]

Just an update on this thread I started. Got some really good info on my problem. I went out and bought a new gas cap and have cut my grass 2 times now with the new gas cap. So far it is running great with no stalling or running rough. Must have been vapor lock. Thanks guys!!!! Will keep you guys updated if anything changes. Jim

 

[LB-1911]

^

TheKohler Manuals & Maintenance section is worth a look to stay ahead of it.

http://www.kohlerengines.com/home.h...s&id=49779345-VQ16-c-VQ6-51488591275-VQ15-1t1

 

[Scotie]

I had the same problem with my 18Hp sears last year. I changed the spark plug Magneto, fuel filter and it still would dies when it got warmed up. Wait 20 minutes and it would run fine for a while. It ended up being the 12-757-09 solenoid on the bottom of the fuel bowl. No problems since.

 

[Streetbu]

When it starts to run rough loosen the gas cap and let us know what happens.

Yep, he beat me to it.

 

[shedfullatools]

My craftsman was doing that, before I bought a new coil I decided to try cleaning all the rust from the flywheel and from the contacts on the coil and it has run as good as ever since. Saved me the money of replacing it, Also I had many people tell me setting the gap on the coil with a business card as a gap gauge doesn't work but I did it anyways (Badass) and it was the perfect gap. Just thought you might try that before replacing the coil altogether Edit: I only read the first page and didn't see the second, guess my post is irrelevant...

 

[kelpaso1]

My craftsman was doing that, before I bought a new coil I decided to try cleaning all the rust from the flywheel and from the contacts on the coil and it has run as good as ever since. Saved me the money of replacing it, Also I had many people tell me setting the gap on the coil with a business card as a gap gauge doesn't work but I did it anyways (Badass) and it was the perfect gap. Just thought you might try that before replacing the coil altogether Edit: I only read the first page and didn't see the second, guess my post is irrelevant...

Who all told you that? I do it that way and works fine everytime

 

[chrispyny]

Jim,

glad you figured out the problem. You should however also check the valve lash.
If you have a rough running engine all the time, or less than optimal power/fuel consumption, OR the biggest tell tail sign, when your engine is hot and you turn it off, and then attempt to turn it back on and it wont fire up, you need to adjust your valve lash.

What happens on many small engines is that the valve lash is so loose to begin with, but the tolerances are tight enough for the valve to provide compression on start up, but once the engine gets hot, everything expands, and gets loosey goosey. Then you get off the riding lawn mower, say to move something out of the way for mowing, and you get back on to start the mower and it won't start. It was running fine, but won't start again until the engine cools down some.

Thats a sign of loose valve lash.

good luck

 

[10% OFF]

Is your Craftsman mower older or newer? Does it have "POINTS" or "CDI" engine ignition? IF it is an older unit w/points, the condenser which is wired between the points terminal and ground, may be your problem. When a faulty condenser heats up, the value changes & your engine will sputter/stall until it cools... when it will easily restart. This is a cheap part, & worth a try.