Hey Bill, Happy New Year, have a older 52-4C hand me down, it was gumed up,pulled back plate and plug,cam cover and vc. Soaked in trans oil for a week, All loose now,cleaned it out and lightly oiled it. Comp. feels good fueled it up with Gloplugboy 24% Nitro,17% Castor,59%Meth.,flip,flip,flip and it started,very cold here,so i let it idle for a while,at half throt. there is a rude snappin noise. I'm swinging a 12x5 wood zinger. To much prop?,to much nitro?,detonation? Any thoughts?