12A 1982 gs

I finished rebuilding the carb and got everything back together, but now she idles at around 3,000-3,500rpm with no choke. I tried adjusting the idle mixture screw (turning both ways because I wasn't sure) and I ended up at the extremities of the turning radius with nothing happening. I checked to make sure the choke was open and that the primarys were closed. They seemed to be but there was also what seemed to be a lot of fuel coming out.
I also removed the rat's nest so I could have made an error there too. Possible problems?

 

Too many changes made at once. Now you've got a mess to troubleshoot.

Is there any tension on the throttle cable that might be raising the idle? Also, the idle mixture screw won't make a drastic change in idle speed, certainly not at those rpm ranges. You want the idle speed adjustment.

I would suggest that you spend a little time over at Sterling's site. He's got all kinds of information there, including a tutorial for tuning the idle. Lots of troubleshooting stuff too.

www.sterlingmetalworks.com Good luck...


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A lot of fuel coming out makes me tend to think the primaries aren't closing. The 2 most common things that could cause it, both of which Kentetsu mentioned would be the idle adjusting screw (look to the right a-ways, and then down a-ways from the mixture screw - it's more horizontal than the mixture screw and looks a bit buried in there near where the cables run to the carb), or it could simply be the throttle cable being adjusted too tight.

If you're virtually certain that the primary plate is closing all the way (you've checked both the above), it's probably a vacuum leak.

There is another possibility, but it's a little more remote - if the secondaries are stuck open a bit, that could cause it too, but you'd see gas coming out of the secondaries in that case. I'm guessing you probably would have noticed it though.

 

on closer inspection something that looks like it should have something attached to it doesn't.

I cant find any clear diagrams what is supposed to attach to that brass nipple there. I'm sure it's something incredibly important.
2 questions:
What is it?
What do I connect to it?

 

Somebody's got to know this.

 

Try over at www.sterlingmetalworks.com/bymc

Sterling will know for sure.

 

I actually just found a proper diagram. I'm near positive that's for the sub zero start assist and therefore probably causing a big vacuum leak. Thanks for the ling though, I'll have to double check with sterling to see if I can just plug it or where is supposed to connect too.

 

It's not a vacuum leak. You haven’t read Sterling's trouble shooting guide

 

the sub zero only opens up on "near ice age" temperatures lol, so no vacuum there unless its freezing where you're at this time of year.

it does sound like a leak tho, but like suggested already, check and make sure your linkage isn't TOO tight.

does it make NO change whatsoever when you lower/raise the rpm?, or if you lower it does stall? same with the air bleed, if you tighten it/loosen it all the way does it stall?

 

Sterling's troubleshooting guide keeps pointing me to fuel pressure. The pump and filter is not stock and installed by a mechanic somewhere when I first go the car a while back. Big mistake I know, never been back.
Though after this it DID idle properly, so unless something has jammed the return line or something I don't think it's going to magically have to much pressure. Yet to test that yet though.

I gave the throttle cable a good amount of slack, it's not overtightened. I tricked it into bogging a little to dip in rpm, anything under 3k and it dies out. When I adjust both mixture and idle NOTHING happens. Maybe 500rpm, but that could also just be it doing it's thing because I'm not getting consistent results.

I have kept tabs on everything I've done, So as ken pointed out, I'm pretty sure my next step is to check the fuel pressure then write a very detailed writeup for sterling to point out where my colossal mistakes are.

 

my throttle return spring was slightly stretched and caused this issue. try pressing the bar on the linkage up onto the senser. see if it drops down. I now have a rubber band in place of the spring untill I rebuild another carb. Carb has other issues too so I'm just going to get it done.

That being said I have a quick question. I know 83 carbs differ from the 79-82 carbs. Can I take a carb off a 81 and put it on my 83? Reason being I can't have my car not running while I rebuild the carb. so I need to rebuild a carb and swap. If it makes a differance I will be stripping this carb down of the smog crap.