You might have a vacuum leak almost anywhere, including around the intake
manifold gasket to the cylinder heads. The best way to find it is to
inspect the hoses as you have done, then take all the vacuum connections off
the intake manifold and plug all the connectors, so that you eliminate
things like a leaking power brake booster or a bad charcoal canister, etc.
If that doesn't help, get a spray nozzle from a can of WD-40 and trace
around all the sealing surfaces on the intake manifold and the carburetor
base, to see if the idle speeds up when you feed in extra fuel somewhere
(the engine must be idling, of course).
Tighten the nuts at the carb base, but don't over-do it. They should have
lockwashers on them, and don't need any other help to stay tight. If they
have loosened up significantly, that is probably because the gasket has
shrunk. Just taking up the slack should help or cure the problem if that is
the case.
Two other likely areas for vacuum leaks are around the throttle shaft and
the choke pull off diaphragm. Just squirt WD-40 on all these locations with
all known vacuum connectors sealed/plugged off, and see if you can find it
that way. If not, your carburetor may have gone out of adjustment somehow.
Dick Benjamin
----- Original Message -----
From: <Imp1983@xxxxxxx>
To: <mailing-list@xxxxxxxxxxxxxxxx>
Sent: Friday, April 19, 2002 10:11 AM
Subject: IML: Carb jitters
> Hi,
>
> I have been having some minor problems with my carb on a retrofitted '83.
>
> It is the factory Carter BBD, 8381S, 2bbl. I rebuilt it about 5 years
ago.
> Now I'm starting to get a lot of stumbling on acceleration, especially
when
> cold. Not too bad when warmed up.
>
> I tried Dick Benjamin's trick of slowly moving a piece of cardboard over
the
> intake and lo and behold when the carb was about 7/8ths blocked off, the
rpms
> increased about 50 and the idle smoothed out.
>
> I have checked all the rubber hoses (I think) and they seem to be fine.
Any
> ideas where else the leak could be? I was thinking of re-tightening all
the
> carb screws and mounting bolts.
>
> Dan Wing
> Imp1983@xxxxxxx
>
> '83 Imp, beige, wire wheels, factory carb.
>
> P.S. Will it hurt anything to add some (blue grade) thread-locker to the
> carb screws?
>
>
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