otrelwood 32 #1 Posted July 8, 2012 We found an 855 with a broken rod. everything looked good except the rod, didnt even have a ridge in the cylinder. anyway put a rod and piston, rings in it. it started very hard, spitting gas out of the carburator until it started. then it ran pretty good ,the spitting stopped 'til we went to start it again .is there probably something wrong with the cam in this engine that is not easily seen that i missed ? Share this post Link to post Share on other sites
smoreau 658 #2 Posted July 8, 2012 Sounds like the intake valve may be leaking. this would cause the compression pressure to push air out of the carb the wrong way. Did you do the valves? Also did you set the points to the s hole on the flywheel? Share this post Link to post Share on other sites
MarkPalmer 81 #3 Posted July 8, 2012 .is there probably something wrong with the cam in this engine that is not easily seen that i missed ? It's possible. In many broken rod instances with K181's the broken end of the rod that's still attached to the crankpin will come around and hit the cam and crack or break it because the clearance is so tight there. The thing is the cracks or break in the cam is often very hard to see, the cam will still spin on its shaft and the engine will still run to varying degrees. If the obvious stuff checks out OK and the problem continues, you might have to open it up again and remove the cam for an exam. -Mark- Share this post Link to post Share on other sites
cjsdad 18 #4 Posted July 11, 2012 .is there probably something wrong with the cam in this engine that is not easily seen that i missed ? It's possible. In many broken rod instances with K181's the broken end of the rod that's still attached to the crankpin will come around and hit the cam and crack or break it because the clearance is so tight there. The thing is the cracks or break in the cam is often very hard to see, the cam will still spin on its shaft and the engine will still run to varying degrees. If the obvious stuff checks out OK and the problem continues, you might have to open it up again and remove the cam for an exam. -Mark- I am on my second tear-down after my K-181 broke a rod. The camshaft fits in the block tight enough, and if it is broken irregular enough it will still work. It will be "keyed" together by the irregular crack. My engine ran good enough to plow snow for several hours before it started knocking again. The knocking turned out to be the camshaft jumping forward as the valve lifters rode over high lift on the cam lobes. The vavle spring pressure was forcing the cam to advance and the valves slamming shut were making the knocking sound. If your camshaft is not locked together tight enough it could be causing the problems you describe! Share this post Link to post Share on other sites
