84 johnson 15hp carb problems

My problems started 2 years ago with fuel issues. Ethynol is the start of the problem. I was amazzed at the amount of water that was absorbed in the tank. It started a steady down hill slide for the year. Last year I started fresh. New gas, New plugs. with a little advice from this forumn I had it fixed or so I thought.I think its flooding out on me..this is the symptom. It starts right up usualy on the second pull.. it idles nice..I put it in gear and give it throttle...it spurters a second and then takes off and runs fine for the most part. I'll get to my spot turn off the boat. starting it again is the problem. plugs are normally flooded. I have noticed something else at medium to low speed the rpms seem to rise in lower on its own. I have taken the carb off and cleaned it up..I'm starting to think that the float valve is sticking open possibly. it has a cork float. Am I looking in the wrong direction?

Re: 84 johnson 15hp carb problems

I always replace cork floats as they will go bad from age and will not have the correct buoyancy after being in fuel over time. Replacing the float vary well could cure thr problem your having, and isn't that bad to do. Check the fuel pump for cracks or pin holes in the diafram that would let gas into the crankcase that could cause the motor to run rich and flood out. Just a thought.
Oldnan570

Re: 84 johnson 15hp carb problems

Those old metal topped carbs are pretty foolproof if all the passageways are clean. Are you sure it is the right carb? However there was not a lot of difference in those older carbs before the plastic topped ones came along. I have never seen a 84 with a cork float as what I have seen they replaced those with a brass float about the late 70s.

Sounds like you need a carb kit & new float. Get a carb kit & remove the welch plugs on the carb, soak the carb, blow it out with compressed air & replace the plugs.

Re: 84 johnson 15hp carb problems

It has to be the right carb. it ran fine all along a very reliable motor. I'm going to clean and rebuild the carb with the new plastic float. and new plugs while I'm at it. and hope for the best.