1970s 75HP Johnson OB Idle Stall
 

we have a 1975 75hp Johnson Outboard. If you have been operating at
trolling speed for 20-30 minutes it will stall. If you try to restart
with throttle 1/3 open it will not restart, but if you put throttle at
wide open it starts always. I wanted to try adjusting the idle fuel
mixture, but cannot find anywhere to do this (Type 1 carburetter). Any
thoughts on what the issue is or how to fix it.

In article .com,
says...

we have a 1975 75hp Johnson Outboard. If you have been operating at
trolling speed for 20-30 minutes it will stall. If you try to restart
with throttle 1/3 open it will not restart, but if you put throttle at
wide open it starts always. I wanted to try adjusting the idle fuel
mixture, but cannot find anywhere to do this (Type 1 carburetter). Any
thoughts on what the issue is or how to fix it.


Does it get faster right before it stalls? This would indicate a weak
fuel pump which doesn't pump well at the idle vacuum pulses.

Does it get slower, and slower, an indication of carb flooding due to
worn needle and seat combinations. This would be cured with a good
quality carb rebuild, and I would guess is more likely the problem
you are having.

I love working on those older medium horsepower Johnson and Evinrude
motors. Really like the triples.

"sailins" wrote in message
oups.com...
we have a 1975 75hp Johnson Outboard. If you have been operating at
trolling speed for 20-30 minutes it will stall. If you try to restart
with throttle 1/3 open it will not restart, but if you put throttle at
wide open it starts always. I wanted to try adjusting the idle fuel
mixture, but cannot find anywhere to do this (Type 1 carburetter). Any
thoughts on what the issue is or how to fix it.


Engine temp is the issue. After 20 min at idle the engine is COLD and needs
a richer mixture. Since there is no way to adjust I did the following: I
bent the floats in the carb up slightly so that there is a higher level of
gas in the bowel.. This will lower fuel mileage slightly but cure your
stalling problem ( if you bend the float too much the engine will stall at
idle when hot)