Engine Problems?

[nheuer]

I think I have a problem but i'm not sure of what it is. After about an hour of running the tractor looses power but stays running. If you shut it off for about 15 minutes it runs fine for another Hour. what could be causing this? Seams like a realy odd problem to me. Nick Heuer

[slb04786]

Could be caused by a lot of things. Could be a partially clogged fuel filter or vapor lock. Check your fuel line when you lose power and see if you can see bubbles in the line. Check to see if the fuel line is too close to the muffler/exhaust causing the fuel to boil. Also check your spark when it's cold and when it's acting up. Could be your condenser or coil causing an inadequate spark. Stan

[charby5]

Hi Nick..Ive had Kohler motors that had done the same thing too..boiling the gas was one and also ive had the valves get sticky in the guides after getting hot ...im not saying this is your problem but it might be..Be sure all your cooling fins and the air intake cover on your flywheel are clear of grass and debris to make sure it isnt over heating from lack of air.I also added a little Sea Foam to the crankcase and they've came out of it ..couldnt really prove if it was the cleaning or the Sea Foam that cured mine but it worked three times in three different motors..hope this helps ..good luck charby......

[MikeES]

Make sure your gas tank is adequantly vented. After running awhile you may be pulling a slight vacuum and starving the carb. Good Luck! Mike S.

[HubbardRA]

You may want to also check your valve clearance. If the clearance is too small, the valves will stop seating when they get hot and the shaft expands making it longer. I have had two engines that had exhaust valves with too little clearance. They acted similar to yours. The time till the problem surfaces is dependent on the actual valve clearance. Yours may not be too far off because of the long operation time till it acts up. I had one that would make one trip across the yard and act up. The other would run for 15-20 minutes of mowing. Rod H.