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Starts fine runs up to RPMs that it should be you start mowing 2 inch tall grass and it just loses all RPMs down to about 1600. Compression is 90 pounds and it seems to be failing the plug to has a new fuel filter on it air filters are coming in but it didn’t make any difference if you took them off and try to run it any ideas on what else to check
I also did a spark test both coils are firing like they should be
I do believe the mower is a 2005 if I’m correct it’s 15 years old can’t tell you exactly how many hours are on it right now because the mower is not mine it belongs to a friend but I think it’s somewhere around 485

All right this is the final follow up with the head pulled the head gaskets were both fine but had one exhaust valve that was carpenter up enough it was sticking it open just a little bit and all the seats look like crap so clean the Valves clean the carbon out of the hands and lap the valves put it back together it seems to be running good enough for him Thanks for all the suggestions and help guys

90 lbs is low, i think maybe its time for a rebuild but startech would know for sure so defer to his opinion

did both cylinders read 90? there is often a slight difference in how they wear so i find it strange if they both were identical

keakar said:

90 lbs is low, i think maybe its time for a rebuild but startech would know for sure so defer to his opinion

did both cylinders read 90? there is often a slight difference in how they wear so i find it strange if they both were identical

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Actually the Kohler motor manual that came with the mower calls for 90 pounds of compression and they’re both close to each other but not right on the same number. Thank you

A friend's Kawasaki-powered Gravely did the same thing. It was a bent pushrod. The engine was only running on one cylinder.

cpurvis said:

A friend's Kawasaki-powered Gravely did the same thing. It was a bent pushrod. The engine was only running on one cylinder.

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that was one of the things I had planned on checking I guess I’ll leave that up to the first thing I do when I get back over there thank you.

rabbit.57 said:

Actually the Kohler motor manual that came with the mower calls for 90 pounds of compression and they’re both close to each other but not right on the same number. Thank you

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ok thats good to know, i was under the impression that 150 was the optimum target for mower engines and it shouldnt be below 100

Loss of power could be a blown head gasket. Run the engine for a couple minutes, turn it off, remove the oil dipstick and look for engine exhaust fumes drifting out of the crankcase.

Affordable in Indy said:

Loss of power could be a blown head gasket. Run the engine for a couple minutes, turn it off, remove the oil dipstick and look for engine exhaust fumes drifting out of the crankcase.

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That was one of the first things I did because I thought it was a blown head gasket thank you

rabbit.57 said:

Starts fine runs up to RPMs that it should be you start mowing 2 inch tall grass and it just loses all RPMs down to about 1600. Compression is 90 pounds and it seems to be failing the plug to has a new fuel filter on it air filters are coming in but it didn’t make any difference if you took them off and try to run it any ideas on what else to check
I also did a spark test both coils are firing like they should be
I do believe the mower is a 2005 if I’m correct it’s 15 years old can’t tell you exactly how many hours are on it right now because the mower is not mine it belongs to a friend but I think it’s somewhere around 485

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All right follow up pushrods aren’t bent for the valves compression will actually pump up to 150 psi Plug Foul the Carbon up pretty good within 30 minutes. I think the hourmeter is wrong because it only shows three digits It’s digital I pulled one head because he thought maybe the gaskets were blown didn’t look like it pretty carbon up though. Does anyone know what the service light is on a 27 horse Kohler V twin I’m guessing it gets run probably 4 to 6 hours a week between mowing and everything else he does with it