I now have a nice clean remanufactured Holley 1920 on my '72 Duster. I adjusted the choke so that there is a 1/16" opening when the fast idle adjustment screw is at the top step. The float is set at 3/16" from the top of the fuel bowl. My car is missing under acceleration and down on power.

I did notice that the choke is closing completely and the fast idle adjustment screw is landing before the first step when I pump the gas to start the car. I'm starting with a clean slate here, so what adjustments do I have to do to get rid of the miss and get my power back? I read the article on choke adjustment, but I'm not quite sure what exactly needs adjusting here.

Joel

Sounds like you need to bend the link rod so the fast idle cam gets ont the highest step when the choke is fully closed.

As for the engine miss, either the carb. is running lean or there is a problem in the ignition system. Does the engine misfire when the choke is part way on?
DD

I had some time yesterday to fool around with the car some more. I decided to try to match the settings on my old carb since it was working well until I cracked it by overtightening. I set my float at 1/4" this time. I used the #56 jet out of the old carb since the new one was only a #55. I also used the choke adjustment rod from the old carb in an attempt to match the choke setting. The results were good. My power is way up and the car isn't bucking and stalling anymore. I still have some bogging when it isn't completely warmed up. I am having a hard time getting it started, so I know that the choke isn't right yet. Should I be starting off on the large top step or the next one down? I have to floor the car to start it. It starts out rough and then gets better in a few seconds, but it really doesn't hit a fast idle.

Joel

Sounds like you are making progress, getting a new carb set right always takes some adjustment work.

Same with the choke settings, try some different settings to see what helps. Your discription of having to floor the gas to get it to start sounds like too much choke. Try to adjust the flap / choke stove spring tension so the flap stays a "crack" open.

Once it starts, the engine should fast idle and the flap should pull open more, this prevents the rough running. Keep adjusting things, chokes adjustment is a "trial & error" process.
DD

I do have the flap open a bit, but I think that the heat stove is putting too much pressure on the choke. The stove in my '69 Valiant is adjustable, but this one appears not to be. Did they change them in '72?

Joel

Some choke stoves have an adjustment nut that you can only reach by removing the stove. If there is no adjustment nut, you have to bend the rod to adjust.

I set mine so that the choke just closes when cold. You can also bend the "pulloff" rod to control how much the choke is pulled off after the engine starts.

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Chuck Rivers, Webmaster

COMPLEAT CHOKE-ADJUSTMENT INSTRUCTIONS IN THE ARTICLES SECTION .

OK,
I think I have the choke working better. The car starts much more easily. Now the car stumbles and hesitates on acceleration. It hesitates and bucks maybe once and then it picks up. I'm thinking of going with a bigger jet. I have a #55 now. My float is set at 7/32" which is slightly lower than spec, but seems to work better. Any advice on how to get rid of the hesitation?

Joel

Does the distributor vacuum advance work properly? Does the accelarator pump squirt gas into the carb righ when you crack the throttle?

A bigger jet will help "cover-up" a lean stumble but be sure you reall need to do this.

Another adjustment is to adjust the power enrichment circuit, this is the "economizer valve" on a 1920. These work off a manifold vacuum signel so first try to advance your timming or adjust the valves for maximum manifold vacuum.

If that does not fix the stumble, you can pull open the power valve and add shims to make it kick-in sooner.
DD

I did notice one strange thing that I can't explain. When I connect the hose from the carb to the air cleaner, I can hear the rpms go down and the engine doesn't sound as strong. Could this be the source of my problem?

Joel