1990 OMC Cobra 4.3l Rochester Idle Problems

[Bronczilla89]

OMC Cobra 4.3l

Well Lets start by saying this is my first post so bare with me. I recently purchased a 1990 Sunbird. First time on the lake it ran well for a few minutes then when I would try and throttle up it would bog down. So following the advice of a friend and past boat mechanic, I rebuilt my first carb. Everything went well, I did the usual stuff, and re-installed it on my manifold. I did adjust the idle mixture needles 1 1/2 turns Counter Clockwise from seat. I fired the engine up with no problem. The idle seems to be stuck at around 1800rpm. I fidgeted with the idle mix screws and it did nothing. I checked all my linkages and am pretty sure that I have them correct. Does anyone know how I can tune this down to around 650rpm? Where can I find a picture of one with the linkages all hooked up and what it should look like?

 

[danond]

Re: 1990 OMC Cobra 4.3l Rochester Idle Problems

Your carb or fuel pump may be leaking fuel into the intake. If that was your very first carburetor rebuild, chances are you did it wrong or missed something.

Also are you adjusting the idle with the throttle cable disconnected?

 

[Bronczilla89]

Re: 1990 OMC Cobra 4.3l Rochester Idle Problems

While you were post I was outside working on it and figured it out...I forgot to take the linkage off while I adjusted the screw. There was no fuel leaking into the intake and I think I did everything right on the rebuild. I did hours of research before I even pulled it off the motor. Now that it idles correctly, I tried adjusting the mixture screws and it seems like it made it worse. I did the above mentioned things and backed off 1/4 turn per try and it only got worse. How many is it supposed to take?