[VonYount]

Hey all,
I just spent the weekend rebuilding the Rochester 2GC carb on my '67 Catalina, but I still have a few things to work out.

Problem: When I push the pedal, and let off, it doesn't come all the way back up. I have to goose the throttle to get it to come back down.

It revs fairly high at idle after it gets "stuck", if I don't goose it back down. EVERY time. As you can imagine, this is a total pain during city traffic, or even when coming down steep mountain hill roads.

Background:
* During the rebuild, I noticed that the choke valve wasn't closing. The metal was rubbing against the inside of the air horn (actually, was wedging against the sides), so I shaved the edges of the choke valve and got it freed up.

* The throttle never "stuck" like this before I pulled the carb off and rebuilt it. And the accelerator linkage itself is fine--no binding.

* The automatic choke was set to 2 notches Lean. I set it back on Index as the shop manual indicates. The spring and piston moved freely when I opened it up.

So it seems like, when I press the throttle, it pulls the idle screw away from the fast idle cam, and the choke closes, at least partially, which moves the fast idle cam counterclockwise and upon slowly releasing the throttle, lands the idle screw on a higher step of the cam.

But I'm at a loss as to where I should be fixing this problem. Why would the choke be closing? Perhaps the automatic choke is to blame? Fix it? Or is there a way to disable/lock the auto choke so that the valve is always open?

thx,
ry

[Tom Vaught]

Turn the Choke Cap until the choke moves in the open direction. To lock the choke in the open position, keep rotating the choke cap until there is no pre-load on the choke blade and the choke blade is vertical. Tighten the three choke cap screws.

To set the choke properly:

Requires more effort. You need to get a copy of the carb rebuilders sheet for your carb and in there will be the specs for the choke blade clearance to the airhorn, the index point (you already have that) and how to adjust the fast idle cam as well as the lenth of the choke rod when the choke is fully open so that the fast idle cam is on the lowest step on the cam.

Hope this helps but a Pontiac shop manual does a MUCH BETTER job of explaining it. Even a Chiltons Manual has the info. Maybe you can read the info at a library.

Tom V.

[VonYount]

Thanks Tom. I'll give that a whirl and report back.

[carbking]

The choke plate was probably sticking because some previous owner had overtightened the aircleaner. Air cleaners are held on by a wing nut, and it just needs to be snug. Tightening with a pair of vice grips will simply pull the air cleaner support in the airhorn casting of the carburetor and disfigure the airhorn.

Lots of possibilities on the throttle, the choke sticking is one.

Jon.

[VonYount]

Thanks Jon. The airhorn did look the tiniest bit "out-of-the-round".

[VonYount]

Worked like a charm. I just rotated the cap counterclockwise to stick the choke valve open, now it's back to normal. thanks tom!