Craftsman 54" lawn trctor with 26hp Kolher engine problems

[xrayeddie]

I am new to this site so here gos. I have a craftsman 54" ut lawn tractor with a 26 hp kolher engine. The mower started running ruff so I changed the oil, oil filter, spark plugs with what the owners manuel called for. It starts right up now but sounds like only one side is firing an then it gets smoother like it should and then goes back to running not at full capacity. I also changed out the fuel filter. It really seems like it bogs down alot on just normal mowing except when it reves up to (sounds like)normal 2 cylinders firing. I am a xray tech for 46 years so when it comes to solving this problem I am a good xray tech! I have had the mower for several years and up till now have had no problems. Thanks for listening

 

[Stimw]

My best guess is water in the carburetor or valve adjustment.
I have a 20hp Kohler that gets water in the carb and I have to rev it then do a full choke to clear it.

 

[xrayeddie]

Also when I changed out the spark plugs, one looked pretty good and the other had alot of black carbon build up on it.

 

[randyjs]

I have the same mower and had to replace the coil last year. The original is no longer available so had to buy a two coil kit part number 25-707-03-S.

 

[xrayeddie]

Thanks randyjs, I will check that out.

 

[DuckSlayer1017]

Mine did that for about 5 hrs before the motor blew up from a broken rod.

 

[JRobyn]

There's only ONE carb, so the problem is not related to the carb/fuel since only one cylinder is affected. Could be in need of valve adjustment on the "bad" side, or you could be having poor ignition due to a failing coil for the "bad" side. One way to check for poor spark is to use (or borrow) and old-school inductive pickup timing light. Weak, unsteady, or irregular flash from the timing light will prove that there's an ignition problem.

- Jay

 

[xrayeddie]

Will work on it this weekend? Thanks all!

 

[crazyal]

I would guess carbon is a sign of a weak spark in your case. But if you haven't figured it out yet I would check the compression. You should be able to buy a gauge from Harbor freight for a reasonable price or possibly do the tool loan from Advanced Auto. Check both sides to see if they are the same.