Holley Hot Air to Electric Choke Conversion

[Hrdlx62]

Hello, I know I know chokes are not for high performance racin' engines but we gotta have our parts runner! . Question is on a Holley 1850 series carb with a hot air choke can a person remove the Carter Climate Control cap and replace it with an electric heated cap or do you have to get the complete conversion kit? Thanks.

[Truckedup]

My expereince is the electrial choke cover replacement works ok...But if the engine is shut down for about half an hour, the choke will come on again when it's not really needed...Some have a temperature control device to prevent this..

[Hrdlx62]

OK, probably better off to spring for the conversion kit then. Thanks.

[Tuner]

You can use the electrically heated choke cover with the original 1850 choke housing. The housing is the same, electric or hot air heated. You need to allow filtered outside air to enter through the heat tube fitting so the pull-off vacuum piston will function normally and to prevent the heating coil from overheating. The air needs to be filtered so the choke housing doesn't get full of dirt. If the choke comes back on too quickly when the engine sits a short time after being run, you can mount the hot water hose for the heater against the choke coil housing. In days gone by this was common practice and many carbs had a sheet metal bracket that held the heater hose against the choke thermostat. You may find the bi-metal choke coil in the electric heated choke to be too soft and it will open too quick and be too lean too soon after a cold start when the engine isn't fully warmed up. If this is the case, put the original 1850 thermostat coil in the electric heated choke. You can also 'fine tune' the choke opening time with a restriction (small orifice) where the air enters through the old hot air fitting. Another trick to slow the choke opening heating rate is to use a resistor, such as an ignition ballast resistor, in the 12V+ feed to the choke heater.There is a small brass restriction insert in the choke housing where it connects to the carb body, probably don't need to mess with that.

[Schurkey]

...and keep in mind that you'll likely have to adjust the stroke of the pulloff piston to get the pulloff to open enough--but not too much.

https://www.chevelles.com/techref/Adjus ... Chokes.htm