Choke help needed on 425

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Old April 28th, 2018, 07:19 PM
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Choke help needed on 425

Hi this evening to the group. We have had a persistent problem on our 1966 Ninety-Eight in which the remote choke attached to the intake manifold crossover section has a prolonged 'on' time. Surely directly implicated, the fact the bi-metallic spring is missing from the heat riser valve on the left side is most likely the culprit, the valve hangs open. We are getting the Thornton dual exhaust manifold very soon, and are not sure if a new heat riser valve will fit both our original one and then swapped to the new Thornton. Does anybody make a electric choke conversion kit that works on a 425 Oldsmobile V-8? I see them listed for Buick, but not our cars. Any help would be much appreciated. Thank you and regards, Howie.
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Old April 28th, 2018, 07:43 PM
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You might have to swap on a newer carb with electric choke to make this work. But Joe P did a sticky on electric choke converstions. Here's the link.

https://classicoldsmobile.com/forums...ke-wiring.html
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Old April 29th, 2018, 06:36 AM
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First, it is likely that the bimetallic spring in the choke has lost tension. Replacing the choke coil will likely fix the problem. There are beautiful 66-67 repops available now.

Second, the choke force (and thus the "on-time" can be adjusted by bending the link. The Chassis Service Manual shows you exactly how to do this. There are calibration notches in the choke arm on the carb for measuring this alignment.

Third, no one makes an electric choke conversion for this divorced choke configuration. You will be stuck with changing the carb. Any integral choke Qjet can be converted to electric by swapping the coil. Of course, the 66-67 425s use a side-inlet Qjet like a Chevy. Any aftermarket Qjet you get will require jetting and metering rod changes to match your engine.
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