Divorced choke adjustment?

[RatRacer]

I've got a '78 Chevy G30 van but due to the emissions exemption for 1 ton vehicles at the time the 400 cid 4V is much closer to the older engines.

Has one of those divorced chokes - bimetal coil spring that mounts on the intake manifold.

It takes forever before the thing gets around to letting the choke plate open, leaving the engine bellowing rich mixture smoke for a while then once it does start to open it's still running at a very high idle for a while after that.

I did replace the choke spring, no help, and it appears I'd have to make the rod longer to adjust it leaner but I see no way to "unbend" it to do that.

Any ideas besides one of those electric choke conversion kits? I'm getting tempted to convert it to manual, or somehow mounting a light bulb around the choke cover to serve as sort of a heater.

[ChevLoRay]

I bought an Edelbrock 1901 Q-Jet and the divorced choke stuff. There is an electric feature on mine, and it has been trouble-free. But based on your comments, it may be that the Choke Pull-Off is bad. It's not hard to change and easy to pick up one at your local parts house. I got my last one at NAPA.

But I'd sure get one and install it before I did anything else.

There are adjustments for the chokes, to set them to a Lean or Rich mixture, but adjusting the choke only does that, and has nothing to do with when the choke opens.

[RatRacer]

Guees I'll start there, thanks.

From what I understand the pulloff is supposed to slightly open the choke after the engine starts, so I assume if it isn't working it may also not allow it to kcik off the highest idel setting?

I've also heard a few other things. I rebuilt the carb before I really started driving it and the base gasket may have been thicker, there was also some mention of a small port in the head that mates up with the intake manifold and allows exhaust gas to run under the choke spring?

[truckster]

There should be a choke pull-off too. It's a dashpot that opens the choke under acceleration. Make sure that's working.

[RatRacer]

Sure enough, the choke pulloff is bad. It tries but just won't travel far enough to open the plate at all.

That'll teach me to check those things a little closer when I've got everything apart, it seemed to move fine with a hand vacuum pump but I don't know how hard a vacuum I tested it with.

So once again the fun of that jigsaw puzzle worth of linkages and, being in a van, I've pretty much got to pull the carb back off just to have enough room to mess with it. For now I may figure out an alternate way to keep the choke from fully closing.