Imperial Home Page -> Repair -> Fuel -> Carburetor -> AFB
Question from Frank (1961):
I have to decide what to do about the Carter AFB in my 61 IMP. Last fall the car stalled on me a few miles from my driveway. I pulled over and noticed gas leaking out of the throttle shaft on the side where the choke is. I figured the car was flooded and waited a while and managed to restart the car and get it home. I pulled the carburetor from the car figuring it was time for a rebuild. My question is how much play should there be in the throttle shaft? Is it normal to get some leakage at the throttle shaft in a flooded state? Can the AFB be rebushed? I have never rebuilt a carburetor but I think I could handle it, but If the throttle shaft holes are worn I would rather not attempt a rebuild. I read somewhere that the throttle shaft leakage is usually not a problem with the AFB because the body is so thick, is this true? I could just buy a new AFB and be done with it but I think I would have to change the choke set up. I have the well type automatic choke and would like to retain the original setup. Any advice would be appreciated
If the shaft is worn and you can move it up and down this will cause idle problem because it will effect vacuum needed to pull through idle circuit. On my car, I O-ringed it at each end of the throttle shaft with a c-clip to hold the O-ring on.
Usually there are brass bushings where the shaft, on which the "butterflies" mount, goes thru the carburetor body.
I feel that these bushings should be lubed a little with a decent spray-oil on a regular basis...or even more frequently if an owner likes using spray carb-cleaner on a regular basis. I use Valvoline Syn-Power in the Gold aerosol can...from Advance, Wal-Mart, etc for lubing the shafts.
This is the way I have seen it done by a mechanic I once knew: He'd rev the engine up, then aim whatever spray-oil at the throttle-shaft using that red-tube extension that sticks in the nozzle and SPRAY...then slam the choke shut with engine revved a bit, almost killing the engine. The logic was that with the dramatically increased vacuum created by slamming the choke shut....that the oil got sucked in, properly lubing the shafts.
Question from Greg (1967):
Anyone know of a good source for a vacuum choke for Carter AFB? I'm debating as to whether or not I want to go electric, or stick with a vacuum choke, after the Carter/Holley swap on my '67.
Reply from Dick:
The original choke is operated by a bi-metallic spring that lives in its little dugout house in the intake manifold. The only vacuum connection is to the choke pull off, which is related but independent of the main choke operation. These chokes were used on many Mopars of the era - I recently replaced one with a used on from one of the IML vendors (Murray Park), whose info I found on the IML vendor list.
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