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nate121080
04-16-2010, 03:14 PM
I have a kohler ch20 that just died on me. Ran a compression test and both sides only measured 25. One spark plug was dry and the other was covered in oil. The engine has 2478 hours so its probably time for another lol. I'm going to tear it down to see what all needs place. Going to go ahead and replace all gaskets, piston rings (maybe even pistons and valves). Anyone wanna take a gander at what this could be and is there anything else I might as well replace while I have it tore down? Thanks

PS. Are these engines sleeved?

piston slapper
04-16-2010, 03:57 PM
If you only had 25psi comp, it sounds like your hydralic lifters are pumped up . This is usually caused by dirty oil or the wrong viscosity oil (needs 10W30) Definitely replace the lifters and check to see if the pushrods are bent.

nate121080
04-18-2010, 11:08 AM
Ok found the problem. The sprocket on the crankshaft had a crack all the way through and a bent pushrod. The crankshaft sprocket is pressed on instead of using a keyway. It has a dot on it that matches the dot on the cam sprocket to set the timing. But my question is where do I need to have the pistons set? Also I cant find a diagram showing I can order the crankshaft sprocket. I found one but with no pic and it was only like $7 so I assumed this wasnt it?

topsites
04-18-2010, 11:11 AM
I think you might be better off just getting another, or maybe short block it if that's possible.

nate121080
04-18-2010, 11:23 AM
Heres the diagram of the cranshaft with the sprocket but I cant find where to order just the sprocket.

nate121080
04-18-2010, 11:27 AM
I think you might be better off just getting another, or maybe short block it if that's possible.

No point in spending nearly $2000 for a new engine with a mower with that many hours. I would buy a whole new mower before doing that. I have another Exmark Zero so I'm not out of work. I'm just trying to fix this to use as a backup since its not worth anything. Thanks for the reply though.

piston slapper
04-19-2010, 10:10 AM
The crank gear is not replaceable. It is a part of the crankshaft. It is also recommended that the camshaft be replaced when you change the crank. The gears get wear patterns and by replacing only one of the geared parts, you might have a repeat failure. Also check your valves, as the pistons may have hit the valves when the engine jumped time.

Sounds like a new shortblock at a minimum.