Stephen Williams 0 #1 Posted September 16 Hi, I have a Wheel Horse with an Onan16XSL engine, I bought it about a year ago and it ran fine for the first six months, however now the inlet valve on one cylinder has developed an annoying and puzzling (to me) problem. The valve tappet adjuster starts to slowly wind itself in until it opens the valve that much that the engine looses compression on that cylinder and of course power. I have readjusted it a few times but after 3 or so hours of use it needs readjustment. I've asked mechanics about it and they haven't heard of this sort of problem, no one has any idea why it happens, Any suggestions? Thanks. Share this post Link to post Share on other sites
lynnmor 7,950 #2 Posted September 16 I would replace the lifter screw, the adjustment is maintained by the friction in the threads, if there still needs to be more friction, replace the lifter. In addition, make sure that the valve end is perfectly square to the stem and also check or replace any rotators and keepers. Now there may be bad news, the valve seat in the block may be loose and needs checked, continuing to operate with a loose seat may render the block worn beyond repair. 1 Share this post Link to post Share on other sites
Stephen Williams 0 #3 Posted September 16 6 minutes ago, lynnmor said: I would replace the lifter screw, the adjustment is maintained by the friction in the threads, if there still needs to be more friction, replace the lifter. In addition, make sure that the valve end is perfectly square to the stem and also check or replace any rotators and keepers. Now there may be bad news, the valve seat in the block may be loose and needs checked, continuing to operate with a loose seat may render the block worn beyond repair. 6 minutes ago, lynnmor said: Thank you, I was hoping that there would be an easy fix but I should've known better. Cheers Share this post Link to post Share on other sites
