.12 nova
 

.12 nova normal engine when new have pinch feeling at the top ,

What would cause after about 3 gallon for the engine too have 2 pinch when you spin the flywheel go up get stuck normal and then stuck again before piston coming down??

Do the crank just spins effortlessly when the piston is stuck at the top dead center?Maybe its just play in the conrod.

When you can turn the crankshaft a lot in the upper position before feeling a pinch again I would say a lot of play on the crankpim. You can see it when removing the engine backplate.