If you are having trouble with the electric choke on your classic 1965 Chevrolet, chances are the negative circuit that supplies a ground signal to the choke is poor. Instead of using a wire to supply the needed signal, Chevrolet grounds the choke through the carburetor body, down through the studs that mount the carburetor to the engine, and finally through the negative battery cable that connects the engine to the battery. The solution is to clean all the mounting connections and use dielectric grease to improve the connections.
Tools Used: Volt-ohmmeter, Wrench set, Screwdriver set, Drill, Dielectric grease, Emery cloth
Connect Electric Choke
Raise the hood of the car and remove the air cleaner. On the passenger side of the engine, located on the side of the carburetor, is a black, plastic housing. It is round and riveted in place, and a single, black wire plugs into a prong that is attached to the choke body. Start the engine and use a voltmeter to test that voltage is present at this connection. There should be battery voltage supplied to the connection when the engine is running. If not, repair the battery voltage supply circuit.
Test the ground supply circuit with an ohmmeter. Set the meter to its lowest ohms setting and measure from the engine to the rivets on the choke housing. In most cases, there will be a resistance reading. The actual reading should be "0" -- no resistance. If there is no resistance and 12 volts is present at the wire connection and the choke is inoperable, the choke coil is defective. Replace the choke coil.
Drill out the three rivets that hold the choke coil in place. The metal retainer that holds the coil is easily removed once the rivets are drilled out, and the black, plastic housing lifts directly out as well. Inspect the coil. If it is broken, or the large connector rivet that holds the coil to the housing is loose, replace the coil.
Reinstall the choke coil by fitting it into place. It is indexed and will only fit one way, however, some models have a small square tang on the end of the inner choke coil. This tang fits over the lever arm that operates the choke. Other models do no have the square tang. In these cases, place the coil to the right side of the lever arm, and twist the coil housing to the left. This will catch the lever arm and pull the choke plate that is on top of the carburetor to the closed position. Fit the choke coil into the index and adjust the pointers that are on the choke housing to the pointers on the carburetor. Set them the pointer to the factory presets, indicated by the longest marks.
Lubricate small, self-tapping screws with dielectric grease. Install the screws through the retainer that holds the choke housing in place, and use a screwdriver to tighten them into the choke mounting on the carburetor. Be sure and size the screws properly. They are supplied in carburetor kits, and locating the proper screws may be difficult. Screws that are too large will crack the mounting.
Unbolt the carburetor mounting nuts that hold the carburetor base to the engine with a wrench. Examine the mounting nuts and studs for rust or corrosion. If they are excessively corroded, extract the studs and install new ones. Use emery cloth to lightly sand the area around the carburetor base where the nuts tighten down. Use dielectric grease to coat the studs and reinstall the carburetor mounting nuts. Test the connection with an ohmmeter. If the reading is high, continue to repair the connection until the reading from the engine to the choke mount reads "0".
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