# Kohler CH20S: Need help with compression specs



## GrassrootsMR (Jun 5, 2010)

Hi. New to this forum but NOT to small engine repair. However, I'm finding it impossible to find the compression specs for a customer's Kohler CH20S. Family code is: JKH624U1G2RA. Model number is CH20S.

Engine cranks freely, won't fire. Getting fuel, air and spark. I gapped and changed the plugs, tested for spark and checked compression (dry). One cylinder is 100 psi and the other is 105, which is pretty well balanced. I'm looking for a spec for the compression to see if this is low, acceptable, whatever. Just running out of ideas. Next, I'm planning to pull valve covers and check the pushrods for damage and check the valve timing while cranking.

Anyway, come on, pros. Throw me some ideas! (please)

Thanks,
Jamie


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## 30yearTech (Sep 14, 2006)

Compression is good enough to start and run. 

Because of ACR on these engines, they generally do not publish compression specs. Kohler recommends a leak down test to determine if there are compression issues.

Have you tried priming to see if engine will start off a prime?

Are you checking for spark with a gap type spark tester?

Does your engine have smart spark?

You can download a service manual for this engine if you don't already have one from the Kohler website.

www.kohlerplus.com

enter as a guest and you will have access to service manuals and IPL's.


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