I was mowing with my lawn boy for about 20 mins tonight and it was running great then out of the blue it died and seized up. I let it cool and it will turn now but I looked in the exhaust and the piston is fryed. will the bore usually clean up or is it most likely junk? will an f series piston work in it if it isn't totally junk? the v pistons are expensive but the f is only 22 bucks. iv about had it with this pile of crap mower. I even mix the fuel rich too. my briggs runs no matter what but for some reason I keep wasting time with these junk lawn boys....