- Joined
- Aug 29, 2016
- Messages
- 9,455
I have a 1970 Johnson 20hp that has a problem that I can't figure out. It starts and runs great, however at about half throttle to WOT, it occasionally feels like I'm hitting something in the water. It happens maybe every 15 to 20 seconds...kind of jolts the whole boat. I've watched the motor, and it definitely shakes it. I'm thinking maybe a misfire, but not sure. Has anyone else had anything like this happen, and can point me in the right direction? It is a pin drive motor, and I've checked that for slippage...it's all good. Below about half throttle, it doesn't do it. Thanks for any help.