Johnny--You are "sort of" right. The trick is that you don't set the length of the pivoting latch to hold the valve absolutely wide open. ---Maybe about 3/4 or 7/8 open. That way the engine can't develop any compression, so it doesn't fire, and begins to slow down.--However--every time the cam comes around it still "bumps" the cam follower bearing and tries to open the valve all the way. As soon as the engine slows down, the governor spring retracts the flyball arms and the pivoting latch wants to retract out of the way. At the next bump from the cam, the pivoting arm is released and falls back completely away from the L shaped latch. Then the engine can fire again and start the whole process over again.