Cold Weather Modulator

1. Cool modulator to below the following temperatures by spraying with Refrigerant 12: black modulator, 20° F; blue modulator, 40° F; green modulator, 50° F; yellow modulator, 65° F. Allow sufficient time for modulator temperature to stabilize and modulator valve to close. Do not spray refrigerant with engine running, as any refrigerant drawn into the carburetor and burned in the engine will produce poisonous phosgene gas. Conduct test in well ventilated area.
2. Use a 24 inch length of 1/4 inch hose between cold weather modulator and vacuum gauge. Using an external vacuum source, apply at least 16 inches Hg vacuum to vacuum motor side of modulator and trap vacuum by pinching hose. The modulator must hold at least 5 inches Hg vacuum for 30 seconds. If not, replace modulator.