Accelerator Pump: Testing and Inspection

LEAKING DIAPHRAGM: Allow engine coolant to stabilize to ambient temperature. Start engine and immediately check for vacuum at the Temperature Compensated Accelerator Pump TCAP valve. When the engine is cold, No vacuum should be present, (at the TCAP valve). Allow engine temperature to reach a stabilized value and check to ensure that a vacuum greater than 10 in-Hg. is present at the TCAP valve. If the vacuum signal to the TCAP valve is incorrect either in the hot or cold mode, check vacuum hoses, connections and the vacuum control valve. After a vacuum is verified, shut-off engine and connect a six inch section of clear tubing (5/32-inch ID) between the TCAP vacuum hose and the TCAP valve. If no fuel is flowing, remove clear tubing and reinstall vacuum hose to the TCAP valve, turn the engine Off.



HOT/COLD FUNCTION: With engine Off, remove carburetor air horn and air horn gasket. If the engine is warm relieve pressure on fuel inlet needle by carefully depressing fuel bowl float, carefully remove float and needle assembly, remove enough fuel from the float bowl so that the TCAP bypass bleed hole (fuel bowl side of TCAP valve) is just at or above fuel level. Remove the vacuum hose from the TCAP valve, actuate accelerator pump - at a moderate to fast rate, observe fuel discharge out of TCAP bypass bleed hose. No fuel discharge should be observed from the bypass bleed. If fuel does discharge, replace valve. With a hand operated vacuum pump, apply a vacuum greater than 10 In.Hg. to the TCAP valve. Actuate the accelerator pump with a very quick action from idle to wide open throttle, fuel should be discharged from this bypass bleed. If fuel does not discharge, replace TCAP valve. Reinstall float and needle assembly, air horn and a new air horn gasket. Tighten screws securely.