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Old 07-01-2005, 10:28 PM
freddyc freddyc is offline
LawnSite Senior Member
Join Date: Jan 2005
Location: Western Ma
Posts: 578
Originally Posted by 97firebird
Oh, here is my problem..still....My 1992/3 Kohler Magnum 20hp motor has been blowing oil out of the PCV valve like crazy and leaking out of the valve cover gaskets...This past spring we rebuilt the following....pistons, rings, honed cylinders, valve job, valve clearance, etc. all new gaskets, new breather plate, breather gasket, and checked the oil pressure regulator. I am sure that I have the correct oil level and viscosity in the motor. All of this still did not solve the problem, although the motor runs beautifully now. Could it be valve seals (There are only valve seals on the intake valves, which I replaced, but have not run the motor with them in yet)? Valve guides? Have yet to check them but I have the specs...It seems as though the crankcase is becomming too highly pressurized and/or filling the valve area up and forcing oil out of the PCV. I have had it with this motor so any help would be greatly appreciated. Thank You

I have a 20hp Kohler Command that is pushing oil out the breather tube. Haven't had time to do any pressure checks yet, motor runs fine, but the air filter plugs with oil over time. I have nothing coming from the valve covers or anywhere else though. If you have access to a pressure gage (manometer) then checking for a pressurized crankcase might not be a bad idea. If not, does the oil flow increase out the breather when the engine is at higher rpms?? Someone suggested that there was a replacement breather for some models..don't know if its true. I saw that if your engine only blows by at igher rpms then its possible that the breather area is too small to vacate the pressure fast enough. Again don't know if its true.

If you've already replaced rings and so on, its almost got to be a breather issue. Are you sure you don't have a port blocked or something? I saw that someone said that Kohler has ports in the cylinder walls and that this also can be a blockage point. If you've had it apart, I'm sure you know a lot more than me about the construction though. When you tore down the motor, did you soak the bloak in any type of cleaner??

Please let me know what you engine is about the same year and I don't want to rip it apart if I don't have to!
Good luck.
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