Question about Kohler CH25 PA-CH730-0040 Command Gasoline Engine
there are no published compression limits for kohler
the prefered method is to have the cylinders leak tested , because of the decompressor action built in while trying to compression test
but off the top of my head most machines would run best with a minimum of 100 psi or better
given that these have a compression ratio of 9:1
you could work it out
9:1 X 14.7 PSI ( 1 amtmosphere ) @ sea level = 131.00 psi
compression ratio = swept cylinder volume + clearance volume (@ tdc) divided by clearance volume
here is web site for obtaing service manual
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select command pro twin -ch/cv 17-26
go to service manuals , select sm 24-690-07 file is 8.82 Mb and double click it and save a copy to your hard drive
cheers hope it helps
Posted on May 07, 2011
Have you checked for a bad head gasket?
Check the intake valve springs or the intake valve shafts to be sure they aren't stuck open. Another cause could be excessive carbon build up on the intake valve causing them to not seal.
If you've gone this far, you could try a compression leak down test. If you still have the push rods out, you can use or get an adapter that will allow you to pressurize the cylinder(s) with air by removing the spark plug. Apply 70-80 psi air directly to the cylinder (the cylinder may go to BDC (bottom dead center) but if you don't have any push rods, the valves can't open.
Listen carefully - if you hear air leaking out of the carb, it's a bad intake valve. If you hear air from the exhaust, it's an exhaust valve. If you hear air from the crankcase breather, it's piston rings.
Posted on May 03, 2009
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