Stuck valves - advice please

[cederholm]

Originally Posted by Mulletwagon

Had the same problem. Shot some Marvel Mystery Oil directly into the carb at elevated rpm and the engine settled down to a smooth idle. My problem was sluggish valves rather than stuck valves. The MMO approach would be a good first step before a more serious tear down. Good Luck.

Thank you, I’ll try it. How do you identify sluggish valves vs stuck valves?