QuestionQUESTION: Rebuilt a Kohler CV-22 after throwing a rod. Installed oversized valves at the same time. After installing engine on mower, it started promptly and ran fine for 10 minutes. I shut it down to finish assembly. Since then, it will not restart but will try to catch occasionally. I know I'm getting fuel and spark. Looking at a compression gauge while cranking shows a dimishing level of compression during the crank, and after maybe six cranks, there is no compression on either side. I thought that maybe the hydraulic lifters were not bleeding after a few cranks, so I installed new ones and they travel well in their bores. Reinstalled on mower and it restarted promptly, then after a shutdown will not restart. I thought that maybe the new valves were tight in their valve guides, so I compared their 'feel' with those from a different Kohler engine - feels about the same. Reinastalled on the mower, started promptly, then after shutdown will not restart. A leakdown compression check shows AOK. What am I missing? Thanks in advance!
ANSWER: Have you checked the flywheel key? Have you checked the oil pressure to see if it is holding pressure? Which oil filter are you using?
Have you performed an engine vacuum check just to see what it is maintaining?
Did you go to Kohler's website and download the engine repair manual?
Let me know.
Eric
---------- FOLLOW-UP ----------
QUESTION: Eric, thanks for the reply. Yes, I checked the flywheel - every time I pulled the flywheel - and it is like new. I have not measured the oil pressure but in my case the oil pressure sensor is disabled. I have not measured the vacuum either. I have read all 217 pages of the Kohler service manual hoping for insight. At this point I suspect that the engine will not restart after it's first run because the lifters are not bleeding down enough to allow the valves to fully close. This is not an issue right after a rebuild because I manually bleed the lifters before I reinstall them. When I check compression on a cold engine, it is maybe 110 psi at first. If I recheck it 10 seconds later, it is 60 psi. If I again recheck it after another 10 seconds, it is below 50 psi. If I wait 10 minutes and repeat same process, I get the same results: 110 psi, then 60 psi, then less than 50 psi. You can see why I suspect something fishy with the lifter bleed. I am using the Kohler recommended 10W30 oil. The lifters are new and move well in their bores. Could the valve springs be weak? The engine has about 1700 hours on it. Maybe I should shim the rockers up a bit?
AnswerDoe the engine have an oil filter? Some oil filter have an anti-drain back valve inside them. Are you using a Kohler oil filter?
Were there any check valves in the oil system that may have fallen out during re-assembly?
What is the engine model and spec number?
Eric
