Briggs 17 H/P 31C707 fuel butterfly came off and engine ran like a 100 MPH before I could cut it off. Found butterfly stuck in exhaust one screw in muffler and other with piston. Put it back in order. After it ran wild when it happen, I had oil pouring out vacum hose to carb. After cranking it is still pouring oil to carb. Could not see any scars on piston wall, but piston head had scars when I took head off. Any one know fix now, and what caused this?
#2
Fish
When you put it back together, did you use a new head gasket?
It is possible that the repeated impact of the piston crown with the foreign objects (screw and butterfly) in he combustion chamber have caused your oil scraper ring land to close stopping the oil scraper ring from rotating. I have had the exact same failure as this on a 31G777 a few months back.
