Hello all. Briggs I/C OHV 28N707 single piston series 14.5hp in an MTD yard machine rider. Engine suddenly turns over very easy with a backfire or two when I try to restart it. No oil leaks from the casing at all, very clean engine actually, with a good maintenance schedule. Pulled the OHV cover, valves are both moving during attempt start. Pulled the complete carb assembly thinking maybe it was a clogged jet. Pulled the spark plug which was oily. did a few compression tests which shows zero. I can turn the motor by hand with little interference or drag. Pulled the engine and disassembled it completely. No scoring, marks, chips, cracks on anything inside or metal shavings. Valve faces look good without chips. Piston has all of its rings and fits snug into sleeve.
Only today did I wonder "can I get a false reading on a compression test if the whole carb assembly was off of the engine"? I know some engines have a fancy "compression release" during starting.
Anyone have any thoughts on what I might consider next?
