340 Chugging instead of Reving

What plugs are you running.


At 180* overlap from #1 compression stroke. The exhaust valve is open and the intake is completely closed. View attachment 1715985344



Ok, if you are 100% sure you are on overlap you need to stop what you are doing and degree the cam. The cam is installed severely retarded. Probably more than 10 degrees retarded. You’ll be lucky if you didn’t bend some exhaust valves being that far retarded.

Again, if you are sure that’s overlap your cam is WAY OFF. That needs to be corrected first before you change anything else.