Tech: Install An Electric Choke On Your Manual Carb

Carb Choke 01

In this age of electronics and bolt-on fuel injection, it still isn’t unheard of to run across an older vehicle-especially one built for performance-that still has a manual choke. That’s exactly what happened to us-well, not exactly. But sort of-recently when we went to replace a gummed-up, worn-out carburetor on our 1978 Camaro that wouldn’t stop giving problems. Instead of going out and getting a new carb, we grabbed a perfectly good Holley four barrel sitting on the shelf that we hadn’t used in a few years.

Of course, we’d forgotten that the carb was set up with a mechanical choke assembly. Instead of bothering with that we simply made a stop at our local speed shop to pick up one of Holley’s electric choke conversion kits.

When installed and set up correctly, an electric choke will get your carbureted vehicle up and running with a minimum of fuss even on the coldest winter mornings. Installing the kit was a snap, and the Camaro has been a pleasure to drive ever since. Our carb is the 4160 Series-style with vacuum secondaries and a single metering plate, but the steps involved are practically the same no matter what type of Holley four barrel carb you are using. So if you are upgrading a mechanical choke carb or rebuilding your old carb with an existing electric choke, we hope our guide will help.

Here's what's included in Holley's electric choke conversion kit. (There are a few different versions so part numbers vary.) Not every component will be needed in every conversion.

Here’s what’s included in Holley’s electric choke conversion kit. (There are a few different versions so part numbers vary.) Not every component will be needed in every conversion.

A manual--or mechanical--choke requires extra linkages which is often more trouble than it's worth. A properly operating electric choke will definitely make your life easier.

A manual-or mechanical-choke requires extra linkages which is often more trouble than it’s worth. A properly operating electric choke will definitely make your life easier.

The first step in the conversion is to remove the manual choke plate which comes off by removing these three screws.

The first step in the conversion is to remove the manual choke plate which comes off by removing these three screws.

Behind the choke plate you will find backing plate which controls the choke rod, as you can see here.

Behind the choke plate you will find backing plate which controls the choke rod, as you can see here.

A small retaining pin keeps the choke rod from falling out of the backing plate's hole. When you remove the pin, set it aside because it will be reused.

A small retaining pin keeps the choke rod from falling out of the backing plate’s hole. When you remove the pin, set it aside because it will be reused.

The fast idle lever assembly is held on with this screw. Remove the screw and the assembly, but save the screw, the wire spring and the smaller of the two levers for reuse.

The fast idle lever assembly is held on with this screw. Remove the screw and the assembly, but save the screw, the wire spring and the smaller of the two levers for reuse.

Here's a shot of all the components in the fast idle lever assembly broken apart. Keep the stuff on the right. Ditch the big lever on the left.

Here’s a shot of all the components in the fast idle lever assembly broken apart. Keep the stuff on the right. Ditch the big lever on the left.

The last piece to be removed is the small gasket which you can see in this photo. Make sure the surface where it attached to the carburetor is clean and the air passage it covered is clear. You can blow compressed air through it, and the air should exit out the bottom of the carburetor. The kit will include a new gasket with a hole it it to allow air through. Ours had an adhesive backing. Install it in place of the old, solid gasket.

The last piece to be removed is the small gasket which you can see in this photo. Make sure the surface where it attached to the carburetor is clean and the air passage it covered is clear. You can blow compressed air through it, and the air should exit out the bottom of the carburetor. The kit will include a new gasket with a hole it it to allow air through. Ours had an adhesive backing. Install it in place of the old, solid gasket.

Reinstall the fast idle lever assembly using the new large lever from the kit and the parts you saved previously. That's already been done in this photo. Here, you see how the choke rod assembles to the new choke housing. Once it is in place, use the retaining pin you saved from disassembly to secure it.

Reinstall the fast idle lever assembly using the new large lever from the kit and the parts you saved previously. That’s already been done in this photo. Here, you see how the choke rod assembles to the new choke housing. Once it is in place, use the retaining pin you saved from disassembly to secure it.

The choke housing is secured to the carburetor at the same three attachment points used for the manual choke plate. Our kit included new fasteners.

The choke housing is secured to the carburetor at the same three attachment points used for the manual choke plate. Our kit included new fasteners.

With the gasket on the choke housing, install the electric choke cap. Notice the metal tab sticking out from the housing. This must fit into the loop on the wound spring in the choke cap. You can check to make sure the tab is in the spring's loop by rotating the choke cap once it is in place. It should open and close the choke plate.

With the gasket on the choke housing, install the electric choke cap. Notice the metal tab sticking out from the housing. This must fit into the loop on the wound spring in the choke cap. You can check to make sure the tab is in the spring’s loop by rotating the choke cap once it is in place. It should open and close the choke plate.

A metal retaining ring holds the choke cap to the choke body. It uses spring pressure to hold the cap in place, so make sure the ring is installed so that it bows outward from the choke cap as you can see here.

A metal retaining ring holds the choke cap to the choke body. It uses spring pressure to hold the cap in place, so make sure the ring is installed so that it bows outward from the choke cap as you can see here.

Here's the upgraded carb installed on an engine. Holley includes the two wires that connect to the carb. The black should go to a ground and the red to a source for 12V fused power that cuts on with the ignition. You can adjust your choke by rotating the choke cap. If the choke comes off too soon, rotate the cap slightly counter-clockwise. If it stays on too long, rotate the cap the opposite directly. Make sure to make only small adjustments at a time.

Here’s the upgraded carb installed on an engine. Holley includes the two wires that connect to the carb. The black should go to a ground and the red to a source for 12V fused power that cuts on with the ignition. You can adjust your choke by rotating the choke cap. If the choke comes off too soon, rotate the cap slightly counter-clockwise. If it stays on too long, rotate the cap the opposite directly. Make sure to make only small adjustments at a time.

Source
Holley
(800) 464-6553
www.Holley.com

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