1979 Mercury 80 horse, will not idle

[*WEAVER*]

I've got a 1979 mercury 80 horse 2 stroke, done a compression check on it tonight, was getting readings of around 120 on all four cylinders. Just had a new stator and trigger put on this thing, thinking that might have been the problem, but not the case.

What the problem is, when I start it, it will sputter for awhile, kinda like it's hitting and missing, and just die. If I lift the warmup lever, it will idle fast,and stay running. Does this sound like a carb problem, a cylinder problem, electrical problem? I can't figure it out, any information would be appreciated. Thanks

 

[ufm82]

Re: 1979 Mercury 80 horse, will not idle

Carb problem. Pull the carb(s) and do a complete clean. Pull the bowls, remove the seats, take out the adjuster screws and completely clean all passages in the carb. Using Carb cleaner, stick the straw IN the ports and blast it through. Poke the straw in every hole and hit 'em. Some will spray back at you but some won't- they'll blow through to where they are supposed to go. Install the idle screws all the way in til just snug and then back out 2 turns. Get the engine started and adjust from there. Once the engine is running, do a decarbon per the proper procedure and she'll likely purr like a kitten.

UFM82

 

[j_martin]

Re: 1979 Mercury 80 horse, will not idle

Sounds like a lean hole or 2 at idle. If the carb cleaning doesn't help, and you've double checked your link n sync, it's time to check the reeds.

I think extreme carboning and/or low octane fuel could do this also. Sometimes a de-carbon routine will fix it.

hope it helps
John

 

[*WEAVER*]

Re: 1979 Mercury 80 horse, will not idle

I appreciate your guys help on this, I took the carbs off, cleaned them out, put them back on, and it did seem to help. I've got to get my idle adjuster screws set right, I'm not real familiar with this, I've got 2 carbs, each with there own adjuster screw, every time I make an adjustment or turn the screw on one, do I do the same to the other? What exactly am I looking for here? Any help on that would be appreciated.

One other thing, I need to buy a gasket set for this carb, like manifold gaskets, and bowl gaskets, where can I get something like that at? Any certain place online you would recommend? Thanks alot.

 

[Chris1956]

Re: 1979 Mercury 80 horse, will not idle

Weaver, The carb kuits are available at any Merc Dealer. You can also order them on line.

Set the idle mixture screws 1-1/2 turns out from lightly seated. Start and warm the motor in neutral, in the lake or bay. Now adjust the idle mixture screws individully, one at a time until the motor runs smoothest and fastest. If you can do it in gear, great. After that is done, try to accelerate in forward. Likely the motor will stumble. If so, open the top carb mixture screw 1/8 turn and try to accelerate. Repeat with bottom carb, if necessary. Eventually you will be able to optomize idle smoothness and acceleration