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Pete R
01-29-2007, 10:05 AM
I rebuilt the Carter AFB on my Avanti R2. Now I am trying to get the car started and noticed that the choke was wide open at 35 degrees F. with the engine cold (even after momentarily opening the throttle). Furthermore, the choke plate has no spring tension to hold it closed when cold. I can increase the spring tension on the choke plate by rotating the choke housing clockwise ("rich" direction), but I have to rotate it maybe an eighth of an inch past all of the index marks. The shop manual simply says to "align the index mark on the coil housing with the center index mark on the choke housing." But that position produces no spring tension. I realize that the thermostatic coil can be installed in four different orientations (only two of them put the hook on the end of the coil in proximity to the choke lever). I believe the coil is installed properly (but feel free to guide me on this). What am I missing? Do these thermostatic springs change (weaken or change shape) with age? Could it be the wrong spring? Are replacement springs available? Why should this one be so far off? Thanks for any ideas/advice.

GTtim
01-29-2007, 04:17 PM
I say turn it to where it seems to work, tighten down the screws and try it out. It could be that somebody has changed the cover, or the spring, or the orientation over the years. If it works, leave it or try to straighten out the appearance issue later. What you want is for the choke to close readily at 35. I like to keep mine a bit on the lean side as the engine tends to go rich just after starting before the choke can warm up and start opening.

Tim K.
'64 R2 GT Hawk

Pete R
01-29-2007, 04:49 PM
Thanks, Tim. I suspect you're right about putting it where it works. I think that's how the Carter carburetor people calibrated the Climatizers. This afternoon I did what any enterprising Studebaker person would do--I took the Climatizer with thermostatic spring from my parts carburetor. I compared it to the one from the carb on the car. Very interesting. The indexing notch on the edge of the Climatizer housing was not in the same place on both housings with respect to the writing on the housings. This leads me to believe that each housing might have been calibrated individually, tailored to its unique thermostatic spring. That is I think the mark on the plastic housing was scribed on the housing dependant on the shape and orientation of its spring and I suspect there was probably quite a bit of variation among springs. When mounted on the car, the parts carb Climatizer housing/spring put what seems like the right amount of tension on the choke plate with the index mark set at the center mark on the metal part of the choke housing--just like it's supposed to. So I think you're right that somewhere along the line something changed or was changed in the housing that wasn't working right. I suspect it will be okay now. Thanks for the advice.

GTtim
01-29-2007, 10:04 PM
Pete,
AFB's were used on a bunch of cars. All of them were a bit different. It's not too hard to imagine that if you took the thermostat housing that seems to be indexed wrong and found the right carb, it would go on with the mark in the right place. As an example, I sent my carb out for rebuilding and it came back with a new housing and thermostat and on the outside of the housing it has a big arrow with the word LEAN by it. Only problem is the arrow points in the wrong direction for a Stude application.

Tim K.
'64 R2 GT Hawk