Small Engines (Lawn Mowers, etc.): kohler command 27 engine issue


Question
QUESTION: my  command 27 ho runs great with no load at about 3800 rpm. compression is good in both cylinders 160/155. when you engage the bladed, still no problem. the moment you put it in grass it looses power & chokes out. It has been at the shop several times, coils good, carb good.. any ideas???

ANSWER: Wore governor spring???  Not likely but it could be the governor spring or something in the high speed circuit of the carburetor.  

3800 RPM is too high.  According to the Kohler manual the maximum allowable high speed for these engines is 3750 RPM.

Did someone mess with governor spring?  We see this a lot...someone messes with the mower and stretches the spring causing the governor not to properly function.

Did you download the service manual?
Eric

---------- FOLLOW-UP ----------

QUESTION: Only person to touch this has been the dealer. The rpm's on the motor are what they were from the factory (hr meter also displays rpm, but could be slightly inaccurate) the dealer is recommending motor replacement. If so..that makes Kohler junk in my opinion.700 hrs on their best motors??? My Kawasaki's have 3-4k hrs & still going strong.I will look at the gov spring.

Answer
IMO, the Kawasaki is a much better engine than the Kohler.

Before replacing the engine I would perform a few tests (below) to help verify the condition of the engine.

1) Leakdown test to check the condition of the rings and valves
2) Vacuum test to ensure there are no air leaks causing a lean condition

It would be great if you could watch the governor when the engine is loaded, blades on and cutting grass, but this is hard and somewhat dangerous to do.

I would also make sure there is no binding in the governor links and I would replace the governor spring...probably not the problem but way cheaper than a new engine.

I still suspect the carburetor is at fault.  What is the engine model and spec number?  I'd like the engine info so I can look up the carb.

Eric