plumb-r 34 #1 Posted August 25, 2021 I have a C145A tractor with a 14hp kohler engine. A few weeks ago it blew the spark plug out of the head stripping out the threads where the spark plug threads in. I located a used head. Cleaned up made sure it was good and flat, new gaskets ect. Plug just blew out again. I did notice the head I removed was super clean no carbon at all on it. If running to lean could it heat up enough to blow out the plug?? Share this post Link to post Share on other sites
lynnmor 6,706 #2 Posted August 25, 2021 If it is running too lean, you may be getting some detonation, so correct a lean condition. It would take considerable pressure to blow a plug straight out, you need to review the deck height (distance from piston to top of cylinder), head gasket thickness and if the head is correct. Check if there is excessive rod bearing and wrist pin clearances. Check the ignition timing. Share this post Link to post Share on other sites
rmaynard 14,805 #3 Posted August 25, 2021 (edited) First thing I would do is a static timing check. Spark plus should be torqued to 18-22 ft. lbs. Edited August 25, 2021 by rmaynard 1 Share this post Link to post Share on other sites