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What's wrong with this Kohler?

Westbrooklawn

LawnSite Senior Member
Location
Durham, NC
OK - here's the story.....

I had a problem with overheating, power, missing, etc. with a 20 HP Kohler on my Walker mower. Certified Kohler dealer works on it and finds blown head gasket on one cylinder and blown intake gasket. He replaces those, rebuilds carb, and mower runs fine. After about 100 hours symptoms re-appear......same mechanic replaces gummed up spark plug on cylinder that originally had blown gasket.....can't find anything else wrong. Now about 100 hours later that same cylinder has plug gummed up with oily black carbon to the point it closes the gap on the plug.

What is causing this? Any ideas???
 

locutus

LawnSite Bronze Member
Location
NC
Sound like you've got oil getting past the rings or valve quides. Does it smoke a lot?
 
OP
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Westbrooklawn

LawnSite Senior Member
Location
Durham, NC
It doesn't smoke a lot. It will smoke some times on start up, but it doesn't smoke while running. The motor has 770 hours on it. Would a compression test rule out rings? What would a good pressure reeading be?
 

Ax Man

LawnSite Senior Member
I think you need to do a leak down test, where you pressurize the cylinder with air and listen for where it is escaping.
The manual says a standard pressure test won't work because of the compression release built in for starting.
I did however test mine without knowing that, and got around 100 psi.
 

barnard

LawnSite Senior Member
Location
central,OK
Bad rings/scored or worn cylinder bore are the likely causes of your problem. I 'm sure your using oil,right . It's not the mechanics fault though as he didnt have to tear down that far to replace the gaskets you mentioned. The probable cause is engine overheating be cause of lean air fuel mixture due to intake gasket leaking . As well as unfilter air entering the engine through the intake gasket leak .
 
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Westbrooklawn

LawnSite Senior Member
Location
Durham, NC
barnard - I think you have hit the nail on the head. What is the best way to fix this situation..........is an engine rebuild the economical way to go or should I get a new engine with new warranty. The new engine would run around $1300-1400.
 

EJK2352

LawnSite Bronze Member
Location
Salem, Ohio
One thing to consider when deciding weather to rebuild or buy new is WARRANTY!!!! Some guy's will give 90 days on a rebuild, some are less and some will offer no warranty at all. If you buy a new complete Kohler Command Pro you will get a full 2 year commercial warranty.
 
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