Emark plug fouling

[tideman7]

I have a Kohler command CH 640 engine on an exmark navigator mower. The left side spark plug keeps fouling out but there is no smoke or much smell to indicate ring problems. Any suggestions? Oil level seems to be correct.

 

[slomo]

Another situation where a PET-4000 comes into play.

Swap plugs and see if the problem follows.

 

[Born2Mow]

• Low compression, most likely due to 1) blown head gasket, or 2) tight valves.
• Poor quality fuel. Ethanol fuel that has sat for an extended time.
• Water in the fuel (Do you pressure wash your mower?)
• Is that the cylinder with the sump breather hose connection? A dirty air filter will make the engine ingest more engine oil on that side.

 

[hlw49]

blown head gasket

 

[tideman7]

• Low compression, most likely due to 1) blown head gasket, or 2) tight valves.
• Poor quality fuel. Ethanol fuel that has sat for an extended time.
• Water in the fuel (Do you pressure wash your mower?)
• Is that the cylinder with the sump breather hose connection? A dirty air filter will make the engine ingest more engine oil on that side.

Thanks for the reply and the suggestions. I will start looking into some of these.

 

[bertsmobile1]

If you have the 2 barrel carb then the main jet on the left may have come loose

 

[Tiger Small Engine]

If you have the 2 barrel carb then the main jet on the left may have come loose

Kohler Commands don’t usually blow a cylinder head gasket, that is more a single cylinder Briggs issue.
Start by removing, inspecting, and cleaning carburetor. Then run it and proceed from there.

 

[bertsmobile1]

Kohler Commands don’t usually blow a cylinder head gasket, that is more a single cylinder Briggs issue.
Start by removing, inspecting, and cleaning carburetor. Then run it and proceed from there.

Agreed
I did not suggest a blown gasket but it is only a 5 minute no tool screening test followed by a leak down if the dip stick smokes or removing the breather fixes the symptoms .

 

[VegetiveSteam]

I have a Kohler command CH 640 engine on an exmark navigator mower. The left side spark plug keeps fouling out but there is no smoke or much smell to indicate ring problems. Any suggestions? Oil level seems to be correct.

I realize this thread is a week old but is it a wet oily foul or a dry foul?