Compression test

[The Cub]

What should the compression on a k 241 motor 10 hp mine is reading 30 psi I'm thinking it should be around 90 of above ?

 

[Gator6x4]

If memory serves the K241 engine had a compression release to aid in starting. (Keep in mind what is said about age and memory). Obtaining or doing a compression check on an engine with a compression release is tricky. If the engine has compression release, 30 PSI on the engine when being spun by the starter may be normal.

 

[Johnny Ducati]

Cub, I have a 12 hp Kohler and I'm not sure of specs, but I doubt 30 psi would be enough compression to light up the fuel. Try putting a tablespoon of 30 wt oil in plug hole, replace plug and try again. If there is a dramatic rise in pressure, you have a broken, worn or stuck compression ring(s). If no appreciable change, you might have a blown head gasket or severely burnt valve(s). Are you opening the choke and throttle before cranking? If not, that will give a pretty low reading (but still should be way above 30psi.

 

[RandyT]

Some of the K series had compression release, and some didn't . It has been my experience as a Kohler tech that with the compression release on that engine you can see readings as low as about 70, but some times you can spin the engine fast enough with the old starter generator setups, that it will close the compression release, and then 110-130 can be achieved.

 

[JRobyn]

You guys know that the OP is from over 2 1/2 years ago, right? Cub might have it sorted out by now.

- Jay

 

[Johnny Ducati]

Right, Jay, Cub has fixed or sold it by now, but the info is timeless and possibly of use to another CC owner.

 

[SandburRanch]

Maybe he has discovered that at cranking rpm the throttle plate is always wide open no matter where he places the throttle lever if it has a constant speed governor.