1976 85 Johnson OMC idle

[76 Glastron]

I'm fixing up a 1976 Glastron tri-hull with a 85 horse Johnson OMC. When i got it the motor was seized and once i freed it up it had no spark or fuel. It's got a new power pack, plugs and used carbs. I have gotten it running and have taken it out. I synced the timing and carbs and everything and it will start and run but won't idle it keeps stalling out and appears to be starved for fuel. I have a service manual but cannot figure out how to bring the idle up without messing up the timing. Any advice?

 

[Daviet]

Re: 1976 85 Johnson OMC idle

First things first, you say the motor was seized, did you check compression? Poor compression will affect idle. There is a slot headed screw about 1/2 the way up the spark advance lever that has a cap on the back side, that is your idle speed adjustment.

 

[iwombat]

Re: 1976 85 Johnson OMC idle

As stated before - compression test and spark check. Assuming all goes well there, rebuild your carbs. You'll need to remove the core plugs over the idle capillaries, and clean them (then replace w/ the core plug in the carb kit). They're most likely all gummed up.

 

[76 Glastron]

Re: 1976 85 Johnson OMC idle

To clarify i've had it running and idleing ok before i didn't have a tach or timing light at that point so i couldn't get everything set where the book wanted it. after replacing a bad coil, power pack and rectifier diode and getting a tach and timing light I synced everything and adjusted the timing to bring it back to factory specs and now the idle is low. I've run spark and compression tests and it all checked out. I rebuilt the carbs two years ago with a complete rbuild kit but I have had fuel issues since then and i've cleaned the carb but i didn't take out the low idle orfices and clean the so thats my next step. The idle adjustment Daviet mentioned is what i keep coming up with but wont that also advance the spark? The service manual says with the warm up lever up it should be at five degrees so thats what i have it set at.

 

[iwombat]

Re: 1976 85 Johnson OMC idle

That 5-degree guideline is simply an indication that everything has been put back together normally i.e. flywheel key not sheared etc. Adjust the low idle to reach the 650-700rpm in the water in gear. The low idle timing will be what it will be. The only adjustable timing is the max advance.

 

[76 Glastron]

Re: 1976 85 Johnson OMC idle

Thanks for replying so quickly. Ill try that adjustment and see what happens.