Distributor Solenoid

PURPOSE
Some engines have a solenoid in the distributor vacuum advance mechanism to retard timing when the throttle is closed.

OPERATION
At a closed throttle--with the idle adjusting screw in the closed position--electrical contacts on the carburetor throttle stop cause the distributor solenoid to energize, retarding ignition timing to reduce emissions during hot idle conditions.

Cold or part throttle starting is not penalized because the distributor solenoid is not energized unless the hot idle adjusting screw is against the throttle stop contact.

NOTE: Ignition timing must he set at closed throttle to give accurate setting.