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1977 75HP johnson doesn't idle won't full throttle without chokeing it.

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bigred1

New member
I had this problem before I rebuilt the engine, installed 1 new piston all three cylinders got new rings all new bearings and seals the reed boxs look good put it all back together and it starts good and runs fine on about half throttle on the warm up lever any lower and it stalls, try to get it in gear and it stalls i did manage to get it in gear once but had to use choke to keep from stalling. i rebuilt all three carbs and still the same thing would appreciate any help i can get.
 
The need to operate the choke to keep the engine running indicates that fuel is not flowing through the carburetor properly.

Clean carefully the brass high speed jets that are located horizontally in the bottom center portion of the float chambers with a piece of solid strand steel wire.... solvent and air pressure just doesn't do that job properly.
 
joereeves said:
The need to operate the choke to keep the engine running indicates that fuel is not flowing through the carburetor properly.

Clean carefully the brass high speed jets that are located horizontally in the bottom center portion of the float chambers with a piece of solid strand steel wire.... solvent and air pressure just doesn't do that job properly.
Click to expand...

thanks i'll try that and see what happens I think I did that when I had the carbs off, but I might have missed it. I installed new factory spec. jets that did not seem to help.
 
1/ Joe is always spot on with his diagnoses (plural for diagnosis, had to look it up...lol).
2/ I just had the same situation on a 9.9 that died and wouldn't keep running after that unless the choke was fully pulled (which is how I managed to get back to the ramp slowly) did the clean up mentioned above once I got home, and it now runs like a champ again.
 
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