Bellcrank adjustments

First of all John, sorry for the delay, been swamped at work (yea, my real job) and haven't been out playing in the shop.

So the early versions of the 4100 had a bellcrank adjustment for adjusting the choke. This was prior to the 1964 major (3rd revision) changeover. Any carbs after this had the nylon choke adjustment and there is no bellcrank adjustment.(remember there are also two type of these one exclusive to 1964 (Usually blue or whitish blue) and then one from 1964 and up which is the standard white or yellowish white from age) REMEMBER SINCE 1964 IS THE PIVOT YEAR, IN 1964 YOU COULD HAVE SEVERAL DIFFERING DESIGNS DEPENDING UPON THE CARBURETOR AND WHEN IT WAS ORIGINALLY DESIGNED.

The bellcrank choke assembly is fairly easy to adjust but requires just a couple of more steps.

After you assemble the whole carburetor (leaving the pan head screw and flat square nut on the bellcrank just a little loose). At this point keep the choke cap off.
1. Open the throttle about 1/2 to 3/4 open

2. Close the choke flap at the venturi completely closed by turning the choke housing shaft

3. Move the fast idle cam up towards the choke housing stop and measure the distance between the choke housing stop and the fast idle cam on the inside back of the choke housing. The fast idle cam is the one with the linkage attached to the bellcrank, and the stop should be a tang cast into the housing. I use drill bit since that is the most accurate way to measure gaps like this. Anything from 1961 on should be set at around 3/64th, so get your 3/64ths drill bit and place it in between the fast idle cam and the stop. It should rest easily between them without having to wedge or having lots of slop.

4. Now just move the bellcrank on the choke shaft and tighten the pan head screw with the flat square nut to "keep" that setting. Make sure its tight (as this is one of the problems with this design) but do not overtighten as that pan head will readily strip. REMEMBER that the choke flap should be also kept tightly closed at this point.

5. Now at this point your bellcrank has been "set"

6. Now you will want to set your Choke plate pulldown adjustment. And unless you have the vacuum piston type of choke will now require you replace the choke cap back onto the choke housing and temporarily adjust it 90 degrees richer beyond the index mark. I USUALLY LEAVE OUT THE GASKET AT THIS POINT TO MAKE IT EASIER TO ADJUST IT AND NOT DESTROY THE GASKET.

7. Depending upon which type of choke pulldown you have (and in 64 you could have 3 differing types. You basically keep the trottle 1/2 to 3/4 open and then press down on the choke flap to keep any slop from messing the measurement (and using the correct drill bit on the front to measure the gap, make the adjustment that your carb requires. (And it widley varies depending upon carb model).

8. Now remove the cap, install the choke cap gasket and reinstall cap setting at the proper adjustment for that.

Now your good to go.

Good Luck,

Bill White
White Automotive