Rebuilding the MC2100 for my '73 F100 (360/MT).

Spec sheet that came with the rebuild kit lists "none" for the choke pulloff setting. I'm kind of respite to set it fully closed, as it doesnt seem right to me.

I was thinking about just doing 3/32" or something. What should I do?

Thanks again

-MK

 

It's not right, you're correct setting it at 3/32", the choke pulloff cracks the choke open about 1/8" once the engine starts, to prevent the engine from flooding out from the fully closed choke plate.

http://www.therangerstation.com/tech..._2150_carb.pdf

 

I've never understood why some rebuild sheets list "none" or have a blank for the choke pulloff clearance. My best guess is that the sheet is assuming you have an internal pulloff piston, which is ancient. Your MC2100 should have the pulloff on top of the air horn behind the throat.

Set it to the closest thing that makes sense in the rebuild sheet; don't set it closed. The pulloff is crucial to the engine starting. When you press the gas pedal to load the choke for a cold start, the tension of the choke thermostat pulls the choke plate completely shut. If the choke stayed this way, the engine could not start. Instead, vacuum generated by the starter cranking the engine over actuates the pulloff, which opens the choke plate just enough for some air to get through. It literally "pulls off" the choke.

 

Thanks all, that's kind of what I figured. I set the pull-off at 3/32" between the top of the choke plate and the back of the opening per one of the rebuild tutorials.

And you were correct, I have the pull-off on the driver side rear of the carb behind the throat.

Thanks for all the help, I'm ready to put the carb back on the truck and start fine tuning. I'm just going to follow the instructions in one of the tutorials being this is my first time doing this.

-MK