Did I blow up my Weber?

[laotsu]

I have a Weber 32/36 on an Offenhauser intake feeding a stock L16. I have been maxing it out lately driving back and forth on the freeway to the local picknpull. one morning I had a hell of a time getting it to start and had to prime it by pouring gas in the carb. It ran fine for the day. the next morning it was hard to start again and then just started racing to like 3000 rpm. if I choke it back it slows down but runs like shit. I have tried the idle screw and it doesn't seem to have any effect. can idle screw tips just break off in the carb?

[datsunaholic]

Well, it's POSSIBLE to break the idle mixture screw, but that's pretty easy to find out- just take it out and look at it.

 

But more likely you have a different issue-

 

1) the throttle is getting stuck partially open.  If that's cracked open even the slightest, it won't be in the idle circuit so adjusting the idle mix won't have any effect.  I've seen carb base gaskets which were badly cut or broke get stuck in the plates, holding them open.  The throttle CABLE can hold the throttle open too, if it's too tight.

2) The idle SPEED screw (which pushes against the linkage, it's not the mix screw) has worked its way in, and is holding the throttle open, or is jamming the fast idle cams so they can't return.

3) Vacuum leak, usually from the carb body fasteners backing out.  More common with adapters, but it can happen with the Offy manifold too.  Or the manifold itself has gotten loose, or you've sucked in part of one of the gaskets

4) Jets that have backed out- which makes it absolutely dump fuel.  I had a main jet back out once, made starting hard because it was flooded due to all the fuel draining out of the bowl through the wide-open jet opening.  But oddly it DID run, just really, really rich.