Join Date: Oct 2001
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Re: How does this choke work?
It COULD be a climatic control choke. I've played with them on a number of old Rochester Qudrajets in Chevy pickups. I don't recall a metal tube sticking out of them though. That argues that it is a vacuum choke.
If it is a climatic (thermal) choke, the hole shouldn't matter. There would be a metal coil inside that looks like the backside of one of those large termometers for the backyard. It uses heat off the mainfold to cause the coil to move, unloading the choke. You adjust this type of choke by losening the cap and turning it until your choke unloads at the desired temp.
I've not played much with chokes that use vacuum to unload them, so I can't say much about them. I've mostly played with climatic or electric or manual chokes. My GUESS would be that the vacuum line would have to be hooked up to a vacuum source that opens when the temp comes up and thus unloads the choke. The electric ones I'm familar with work this way, with an electric temp sender.
Let us know what you come up with!