Lawn tractor troubles.......help!!!!

shawn474

I have a ten year old craftsman lt1000 that I bought new. It has had pretty regular maintenance but had been giving me trouble since the end of last year in terms of starting. So before storing it for winter I drained the gas and took out the battery. Before this season, I put new gas in the tank with some stabilizer and bought a new battery. All was good the first time I mowed the lawn. The second time, it ran for a half hour and would sputter, rev and die. If I let it sit, I could restart it but the whole process would start over again. I too, it to the local small engine repair shop and $175 later he rebuilt the carb, replaced the lil and filter, changed the spark plug, put on new blades, leveled the deck and a couple other minor things. I got it back and it did it again the first mow. So I did some research, talked to some friends and family and troubleshot. All signs pointed to a failing ignition coil so I ordered a new one and replaced it. Same thing happened. Replaced all fuel lines and filter, adjusted the valves to .004, sea foamed the engine.........it still happens. I get about halfway done with my back yard and it sputters, revs and stalls - acts as if it is flooded. If I let it sit for 10 minutes or so it starts right back up and I can get another 10 or 15 minutes before it happens again. I am at a loss as to what the problem could be. I fear it may be a blown head gasket and if so, it's time to get a new tractor. I also don't want to continue sinking money into it, but in poker terms I a, pot committed at this point.

So I guess I am just asking if any of you have experience with this stuff and what else could I look for?

It is NOT the gas cap........

Thanks in advance,
Shawn

rpf65

I would probably check to see if there is any garbage in the carb bowl. Have a very sillier sounding problem with mine. One bolt under the bowl and it's off. Remove the fuel line, the float drops when the bowl is removed.

F1nut

It's not a head gasket either. It would be blowing smoke out the exhaust if it was, the spark plug would be covered in oil and your oil level would drop quickly.

Sounds like some sort of fuel issue, vapor lock?

motorhead43026

you need fuel, ignition and compression. If you have fuel and spark, check compression when hot.

shawn474

F1nut wrote: »

It's not a head gasket either. It would be blowing smoke out the exhaust if it was, the spark plug would be covered in oil and your oil level would drop quickly.

Sounds like some sort of fuel issue, vapor lock?

I will research this as well and see if I can diagnose it......


How would one check compression when hot? And what would the fix be if compression is compromised?

SCompRacer

Check for proper fuel filter. There are different micron ratings for gravity feed versus fuel pump systems. I have read instances where sears used wrong part number for fuel filter in manual. The engine manufacturer gave correct fuel filter part number to owners. IIRC 75 micron or larger is for gravity systems. 30 and 50 micron are for fuel pump systems.

If you have fuel pump, it could be a vacuum operated type and be faulty.

shawn474

I have the 75 micron fuel filter. It is a gravity fed system. Looking over quickly it seems that vapor lock is a likely cause. The fuel line runs pretty close to the exhaust and the muffler gets really hot really quickly. I may get some longer fuel line and reroute it or wrap in the insulation. Also, I will take off the engine shroud and clean all the fins and get all the debris out. This sounds to be my exact prOblem, but will also check the carb again.

Thanks for all the input.

nguyendot

If that's the issue, heat wrap it and see if it takes a lot longer to happen.

tonyb

You would think if the fuel line was too close to the exhaust, this problem wouldn't have waited 10 years to show it's face.

Sounds like a fuel or vapor lock problem like others have said. Check any hoses for leaks, easy things first. If you just had the carb rebuilt, I'm sure he cleaned the bowl.

Does this problem happen when your flat or on a steeper grade ? Fuel filter and pump are also a possibility. Lawn mower engines aren't too complicated. OIL-Fuel filters and pumps, carbs, vacuum, spark. Process of elimination with the easy stuff first.

msg

flaky safety switches, perhaps?

shawn474

OK so I wrapped the exhaust and no difference. I ordered a new gas cap just in case something internal in the cap (a piece of debris stuck) was causing it. I used carb cleaner on the carb and made sure there was nothing in the bowl. I am starting to think it may be a switch like msg questions. Will try to disable the safety switch and see if that works and replace it if it is in fact the switch. I inspected the breather hose and everything looks intact - no cracks or holes.

Tony, flat, steep, hill, mound - doesn't matter.

charley95

Maybe check over at the lawnmower forum.com

oldmodman

Remove the gas cap and run the mower.
If the problem goes away you have a bad vent in the gas cap.
Replace it.
It's amazing how often they go bad. Either from crud blocking the vent hole or just from corrosion.
If you want to do the test without running the mower pull the fuel line off the carb and let it flow into a can. If it slows to a trickle or stops completely then flows like gangbusters when you loosen the gas cap you have found your fault.

shawn474

Yeah I am going to buy a new gas cap just in case. Also going to try 89 octane gas. If nothing works, every time it stalls will be a beer break.......win win either way

jeremymarcinko

DSkip wrote: »

Just simplify and go all-natural:

Geesh I think I would need to update my tetanus shot before I mowed the lawn.

shawn474

So thought I would report back.......after a bunch of troubleshooting I was able to spend some time this morning trying to diagnose the problem. Double checked connections and everything - still seemed fuel starved so I focused again on the carb. The antibackfire solenoid wasn't clicking on startup so I thought that was the culprit. I ended up taking it off and testing and sure enough it would only magnetize intermittently when tested. I snipped the "plunger" piece off with a pair of wire cutters and started it. It ran for 45 minutes and purred like a kitten. No problems at all, except I will be wearing earplugs as it backfired right after I parked it and turned it off. Scared the bejesus out of me!!!! Ordered a new solenoid and will be here soon. Thanks all.

Nightfall

The ethanol in gasoline now-a-days wreaks havok on small engines. See if you can find some real 100% gas near you.

http://pure-gas.org/

F1nut

No problems at all, except I will be wearing earplugs as it backfired right after I parked it and turned it off.

Must be what that person heard at Walter Reed the other day.

steveinaz

Nightfall wrote: »

The ethanol in gasoline now-a-days wreaks havok on small engines. See if you can find some real 100% gas near you.

http://pure-gas.org/

Exactly. It's a hidden "got'cha" for sure.

tonyb

Ethanol fuels should also be avoided in marine use, and your classic cars....if you cherish them anyway.