1980 140HP Johnson Running Rough

[iguana77]

I have a 1980 140HP Johnson V4 outboard. It idles fairly well. At about 1/3 to 1/2 throttle it starts sputtering and will sputter out and die if left in this position. When I move the throttle past a certain point it will clear it's throat and take off as it should. Does this sound like a carburation or a timing problem? I don't see any adjustments on the carburetors and I don't have a clue how to time one of these. Any help would be appreciated.

 

[Haffiman]

Re: 1980 140HP Johnson Running Rough

It sounds like a combination of intermediate circuit in the carb(s) blocked and perhaps a synch issue between carbs and ignition.

 

[emdsapmgr]

Re: 1980 140HP Johnson Running Rough

Looks like the mid jets on your engine are just above the mains, on the side of the carbs. Before tearing the carbs down, I'd probably pull the mid jets out and see if there is any debris/restriction in them. If nothing is apparrent, then pull the carbs apart and overhaul them.