1969-70 80 hp mercury Idling issue

shawpdx1

Petty Officer 1st Class
Joined
Apr 29, 2009
Messages
294
Its almost like its dropping a cylinder at idle . Ive checked timing, done a link and sync, rewired the complete motor, compression is at 150 on all 4 cylinders,
I have not looked at carbs yet but they seem o k. Ideally would love this thing to purr I also put a new impeller in it does not over heat put does not pea real strong, I have put a wire in there and its clear as well as tried to suck out and blockage. I know its installed correctly I did it myself,, had it out on the water and it just dies for no reason but when it runs it pushed my 17' boat about 45mph
 

Moody Blue

Captain
Joined
May 24, 2004
Messages
3,136
Re: 1969-70 80 hp mercury Idling issue

Its almost like its dropping a cylinder at idle . Ive checked timing, done a link and sync, rewired the complete motor, compression is at 150 on all 4 cylinders,
I have not looked at carbs yet but they seem o k. Ideally would love this thing to purr I also put a new impeller in it does not over heat put does not pea real strong, I have put a wire in there and its clear as well as tried to suck out and blockage. I know its installed correctly I did it myself,, had it out on the water and it just dies for no reason but when it runs it pushed my 17' boat about 45mph

Based on what you've done so far and the symptoms you describe, I'd say that the carbs are the most likely cause despite the fact they may seem OK.
 

shawpdx1

Petty Officer 1st Class
Joined
Apr 29, 2009
Messages
294
Re: 1969-70 80 hp mercury Idling issue

thanks was going to pull them this weekend and rebuild them and look at reeds . my throttle advance is REALLY stiff as well I lubed the Zerk loosened up some but does not seem loose enough wont spring back well after throttle up strange
 
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