got a 73 GMC and having problems with the idle

[sampsonjoseph]

I have a 73 gmc 1/2 ton 2 wheel drive.  It has a 250 inline six with a 1 barrel carb.  It runs awesome on the road and even if i start it up to idle it rum great, but about 50% of the time when i go to stop at a red light or stop sign it dies.  No sign of a miss or anything it just dies, but it starts back up right away.  I just put a new carb on it 4 months ago and it couldn't have run any better, but now it won't stay running when i stop.  I dont understand it.  I've changed fuel filter, run fuel additive in it, checked for vacuum leaks, and adjusted it also.  Whats the problems

[Lt.Del]

i would think it was a vacuum leak, but you said you checked that.
Did you try bumping up your idle screw to higher idle rpms?

what kind of tranny?  auto or standard?

If all that checks out, i'd probably look in the fuel bowl, maybe the float needs adjustment for the needle valve.

[sampsonjoseph]

Yeah I already bumped up the idle.  So I noticed last night that the top gasket was leaking gas but all the screws are tight.  I went and had a quote on rebuilding my carb they told me 100 to 120.  For that much I might as well buy a new one.

[Marc]

If they are good at rebuilding carburetors it is probably worth it.  Carbs can be hit or miss "new".  How is the points and condenser?  Is your timing on?

[sampsonjoseph]

When I got the truck the distributer had been changed to an HEI and it is in time.  It runs good out on the road and starts up first hit.