Mercury 80 idle problem

[fishdog4449]

1980 Mercury 80 running very rough at idle. Timing is set at 4degrees at idle, carbs have been cleaned and new fuel lines. engine starts up fine, runs well at higher rpms. Idle mixture screws are set at 1-1/2 turns out. heres my question, when the mixtures screws are turned in to about 1 the engine smooths out but idles much faster; however i have been told this is way to lean. pulled plugs wires off one at a time, noticable drop in rpm for all except bottom cylinder which i could not check. any other culprit that would cause bad idle?

 

[Laddies]

Re: Mercury 80 idle problem

Your problem is obviously the logo on your Avatar on the merc forum.
As far as your engine set the carb were ever it idles best while in gear and then adjust the idle speed with the idle screw don't worry about the degrees of timeing thats only a start point like the number of turns open on the mixture screws.

 

[fishdog4449]

Re: Mercury 80 idle problem

oh i just like the look of the old omcs.
ok thanks will do that!

 

[fishdog4449]

Re: Mercury 80 idle problem

I replaced two plug wires and it runs a bit better, but still a bit rough. I don't know if I'm being too demanding of a carbed two stroke, but since its a four cylinder I think it should run much better. Heres a vid of the motor running...any feedback??

Its a .mov file...http://www.sendspace.com/file/aar4al

 

[Laddies]

Re: Mercury 80 idle problem

Sorry, but your download link looks like someone try to sell me something.

 

[fishdog4449]

Re: Mercury 80 idle problem

Sorry i guess it does. Sendspace is a site where you can quickly host files such as movie files (what i did) that are too big to email or put elsewhere.I frequently use it to transfer files between my laptop and desktop computers. At the bottom of the sendspace page there is a download link for the video of the motor if you still want to look at it.