fuel/air ratio too rich at idle

[dacton]

Hi guys, I am puzzled. I am trying to adjust the idle air mixture needle on my 15 HP 1988 merc. with Wolbro carb. I have removed carb and installed new needle, float, diaphrams and gaskets. while apart, soaked in carb cleaner and blew out all orfices. Before reinstalling carb I put a fuel line on it and pressured it for ten min. to see that there was no flooding or fuel diaphram leaks. After installing it and starting engine I find too much smoke. Adjusting mixture scew in till it is lightly seated the engine begins to run better but is still too rich. I
lowered float but still find it too rich and wet plugs.
Does any one have an idea that could help me out?

 

[saumon]

Re: fuel/air ratio too rich at idle

Usually, you should start you adjustements by lightly seating the idle mixture screw AND backing it out 1 1/2 turn...

 

[dacton]

Re: fuel/air ratio too rich at idle

Usually, you should start you adjustements by lightly seating the idle mixture screw AND backing it out 1 1/2 turn...

Thanks for replying. If I back out the mixture screw the engine runs worse. I originally set the screw two turns out to get started.

 

[saumon]

Re: fuel/air ratio too rich at idle

Adjusting mixture scew in till it is lightly seated the engine begins to run better but is still too rich.

I think that fully seated wasn't over-rich but, on the opposiye, extra lean and you risk ruining your engine...

 

[dacton]

Re: fuel/air ratio too rich at idle

I think that fully seated wasn't over-rich but, on the opposiye, extra lean and you risk ruining your engine...

I found the problem. The check ball in the primer was incased in the spring just enough to prevent it from seating. It looked ok to me before, because this carb is new to me. It is back together and running in a drum and looks ready for the lake when the ice is out.

 

[saumon]

Re: fuel/air ratio too rich at idle

Glad you found the problem!