1977 85 Johnson exhaust issue

[Jmcjunkin3]

Hey there iboats! This is my first official post but this forum has helped me a few times already. I've just pulled our old family boat out after it's sat for a few years, I've rebuilt the carbs, put new spark plugs in it, new fuel lines, and seafoamed it. I chased a misfire and fueling issue and am currently waiting on a couple ignition coils and a new fuel pump. Anyways...I've noticed that there are some exhaust gases coming up from under the carbs somewhere, to the point where the engine doesn't want to run with the cover on....I'm going to try to run some fresh gas without seafoam in it to see if that'll remedy the problem, because it always ran good the way it sat....I've read into taking the powerhead off and it definitely seems manageable. My question is, is the main powerhead gasket the one I need to be replacing? Where the powerhead meets the leg? Thanks in advance!

 

[Bosunsmate]

That sounds like its the culprit. Its not that hard a job so long as the bolts holding the motor on arent seized which is often the case with a salty. The motor isnt that heavy, but if you remove the starter and flywheel it will lighten it up more than some.
I always find removing the LU is best beforehand too, that way when you go to put the powerhead back on you dont have to be concerned with getting the cranksplines lined up without damaging them from the engines weight. It also enables access to change over the impellor which you would want to do after it sitting for that long

 

[F_R]

By any chance, are you running it in a tank? Smoke from the tank will come up from below the carbs. Not a problem on a boat on the lake where it was designed to run.

 

[Jmcjunkin3]

Bosunsmate, I had the lower unit off and actually replaced the impeller due to lack of cooling...but I have also heard that this makes it much easier to remove the powerhead so if I go through with it, I will take the LU off forsure. F_R_, I am indeed running it in a 55 gallon drum, I guess I didnt think of that...I'll replace the pump and coils and take it out on the water. very excited. thanks so much for the replies!!