Correct me if Im wrong, If you turn the mixture screw in all the way and then back it off all the way there should be a huge difference in the way the engine runs. Right? Well when I do that it stays the same. I cant set the mixture, the idle jumps around all over and It missfires every once in a while. Carb was rebuilt a year ago and ran fine up untill last week. Im sooo frusterated:mad:

Dan

Make sure you don't have any vacuum leaks or gaskets leaking. I had a similar problem with my SBC, turned out the nuts securing the carb to the manifold had backed off a little allowing the engine to suck air under the carb. I snugged the nuts down, put a little thread lock on it and have been fine ever since.

Troy

Carb is nice and tight. But on another note if you manually turn the throttle linkage on the carb fuel sparys out. Is feul suppost to come out of bothe sides(both jets) or just one?

I'll bet you a $100 CDN that you have a leaky manifold gasket

:flipoff2:

If I was having the problem that you describe, I would pull that screw all the way out and shoot some carb cleaner down the hole that it just came out of. Not saying it will work but it can't hurt. There is a little, tiny hole at the bottom that connects to the carb throat, and if it gets plugged then the screw won't do anything.
Yes, hook a vacuum guage to the manifold and see what it's pulling. It may be more involved than just a squirt from a can.

good luck

Greg

Did a new manifold gasket, busted that last bolt in the head:mad: Still cant get it to work.:mad3:

I hate my life

DON'T HATE YOUR LIFE!
Allow me to do that for you.
You busted off a bolt?
Big deal, you should have studs there anyway.
I buy a new set of studs and nuts every 3 or 4 manifold changes.
You have to take that manifold off now, might as well get the right stuff to put it together again (you don't want to have to do it over again, right?) Check your mating surfaces with a straight edge. Machine as necessary, DO IT RIGHT THIS TIME! No room for shortcuts here. Some people use two gaskets-the good ones with metal on both sides- and some of that copper gasket sealer all over everything. You can torque the nuts a little more than the manual says, the nuts will strip before the block does (buy an extra stud or two). Once you get the obvious out of the way we can worry about details like idle mixture screws.
If you wanted something easy, you could have got a Corolla.
You got something with character, your going to have to work at it.
We're with you, man.

2f? Pull the carb off and look at the crack on the floor of the manifold :rolleyes:

no cracked manifold. its good:p

If it's a 79, you should have a long hose that come over the back of the motor from the PCV valve.

It plugs into an elbow below the carb on the driver's side face of the intake manifold.

i had a wicked leak there before i desmogged (and blocked the bugger off) and it made my truck run like ass. just like you've described.

I would hunt around for a vacuum leak. Also, both barrels should not open, only one should,depending on how far you're opening the throttle.

With a can of ether, brake clean, or other flammable fluid, spray the carb mating surfaces and the manifold surraces. If yo

Once you've found the leak, screw the mixture screw in all the way, then back it off 1 1/4 turns. Then adjust your idle screw on the firewall side of the carb so that it settles around 600/650 rpm.

now, take it for an italian tune-up (drive the piss out of it) to get those plugs clean.

HTH
Rob