I just purchased a 86 truck with 86k original miles. since 08 it had about 1000 miles put on it. it starts but idles very rough and is blowing black smoke. at higher rpms it dosnt miss but lower it runs like crap. new cap rotor wires filter plugs etc. its carb is clean, at least in float bowl. float appears fines. vacuum lines seem fine. ive driven around 100 miles and used $50 in gas. What the heck is the problem? should i rebuild the carb? Please help.
warren
wjaur AT yahoo Dot com
760 805 1303

thanks

 

Might be running a little rich, LOL. I would assume a carb problem. I have an '84 22r and it was doing the same thing. Turned out to be the AAP(auxilary accel pump?) had a small leak dumping in way to much fuel. If you know a little bit about carbs, buy a rebuilb kit and go for it.

 

http://www.bluebassdesign.com/boonin/carb_faq/

And x2 on the above post. Pull the line going from the AAP of the carb, at the BVSV and see if gas runs out.

 

Thanks for the advice guys. you said to check the aap and you were dead on. runs like a champchamp.wjaurwjaur@yahoo.com

 

sweet! ahhhh.... I love it when a plan come together..

 

Can I jump in here with a question? I seem to have the same problem and wanted to check the AAP to see if it's leaking. Does the motor need to be running when pulling the line or will gas come out even if the motor is not running?

 

I would think it should be checked with the engine not running. Otherwise the vacuum would empty gas out of the tubing. That's a guess though. My truck has the same problem, so I need to check it out, too.

 

the aap is a good place to start,you might also try checking the choke.

 

I checked the AAP, the thing that's yellow on one end and black on the other. It seems to allow flow one direction but not the other. For $15 I think I'll replace it, and see if it helps. Didn't see any gas in the line to the vac port. I hear some kind of leak, so I think I'll replace the old vacuum lines while I'm at it, on general principles.

 

That black and yellow thing is the VTV, looking at my book. I found the AAP, but it seems OK. That is a complicated bunch of emissions stuff there.

 

thanks Gnarly4X, I think I'll replace it and see if it helps. Can't hurt, right?

 

Looked at the AAP, and the diaphragm looked fine. Still running rich.