midsized johnson
Petty Officer 2nd Class
- Joined
- Jul 28, 2005
- Messages
- 155
My 70 has developed a strange issue. It idles and will run fine to near WOT, then bogs when the throttle is pushed all the way. We ran the boat with the cowling off and my buddy throttled it up by hand and it bogged, so it clearly is something happening in the fuel/air mix and not electrical. We sprayed carburetor cleaner on the intake between the carb and the intake and it kills the engine on the middle and lower carbs idling in the driveway. We checked the butterflies with the throttle pushed up to where it ran at 4500 or better, they looked barely open. I pulled the carbs and the intake off and the gaskets all look good and the carbs/intake appear to be in good shape with no visible cracks or pits on the gasket surfaces. Reeds are all in good shape as well.
Also, while at idle, if you put your hand over the front of the carbs, one by one, it will kill the engine. Don't know if that is meaningful to the question, but it occurs to me that if there were a significant air leak then that wouldn't kill the engine.
I've got new gaskets for both sides of the intake, going to put them on using OMC's gasket sealer stuff to see if that makes a difference. At this point, it doesn't seem to me that this is going to fix the problem.
Any thoughts for what could be happening? Am I missing something?
Also, while at idle, if you put your hand over the front of the carbs, one by one, it will kill the engine. Don't know if that is meaningful to the question, but it occurs to me that if there were a significant air leak then that wouldn't kill the engine.
I've got new gaskets for both sides of the intake, going to put them on using OMC's gasket sealer stuff to see if that makes a difference. At this point, it doesn't seem to me that this is going to fix the problem.
Any thoughts for what could be happening? Am I missing something?