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Kohler ch18 questions

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Well, my free to me 918H is still not running well, so this morning I put a new set of plugs in.  The left bank plug was black, the right looked really good.  I removed the air cleaner and ran some carb cleaner thru it.  It ran better but still not well.  There is oil around the air cleaner when I take it off, but when I run it without the air cleaner there is no oil at all coming thru the breather tube.  Also, there is alot of crankcase pressure, when I take the oil filler cap off it blows pretty good.  This engine was overhauled (not by me) three years ago and ran good until last August, when it started running poorly.  I am thinking the breather should be changed, but am I looking at a major teardown?  Can I work on the valves on the left bank without removing the engine?  I am not sure if I am facing valve or ring problems, but because of the recent overhaul, I am doubting rings.  This is my first Kohler so I am learning as I go.  What do you guys think?



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Breather isn't bad but you will likely need a new gasket for the cover.   Will need engine out to get shroud/manifold off for either head. Lifters are hydraulic so there's no valve lash adjustment.  Download service manual from Kohler site.  It will tell you everything you need to know.


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Thanks Carl, as I read more and research more, I am leaning toward a bad head gasket on that bank.  Guess the engine will come out and we will go from there.  Is it ok to change just one side for head gasket or should I do both?



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Should do both.  Kohler has updated the headgaskets for the Command to help prevent blowing them out due to backfire at shutdown.  A good Kohler parts supplier is OPEengines.com.  Also you may want to wire in a normally closed, momentary open switch into the wire to the idle stop solenoid. on the carb to prevent backfire.


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