45-100
Member
My apologies if this has been covered before. I have an early model 4020 with a Stanadyne DBO-1578 injection pump. Several years ago I had the pump rebuilt by a commercial rebuilder. I have less than 100 hours on the rebuilt pump and the engine starts speeding up on its own, without moving the throttle. Everything I have read suggests the governor ring in the pump is bad but I would think it should have been replaced and possibly updated. Is there something else that would cause this to happen?