Fast Idle Unloader
Fast Idle Unloader TestCOLD ENGINE
1. Disconnect the two hoses from the fast idle unloader.
2. Open and close the throttle fully to engage the fast idle cam.
3. Start the engine.
The engine should run at fast idle.
- If the engine runs at fast idle, go on to step 4.
- If the engine does not run at fast idle, check the operation of the fast idle cam.
4. Connect a vacuum pump/gauge to inside fitting of the unloader and apply vacuum.
The fast idle speed should drop.
- If idle speed drops, reconnect the hoses and go to on to right column for hot engine inspection.
- If idle speed does not drop, check the unloader for leaks, blockage or damaged diaphragm. Remove the choke cover and check the unloader rod for free movement. Repair or replace as necessary.
5. Reconnect the hoses.
HOT ENGINE
When the engine warms up, its speed should drop below 1,400 rpm as the unloader pulls the choke linkage off the fast idle cam.
- If fast idle drops below 1,400 rpm, go on to the fast idle check. Testing and Inspection
- If fast idle does not drop below 1,400 rpm, disconnect the two unloader hoses, and check that vacuum is present.
- If vacuum is present, check the unloader for leaks or blockage. Remove the choke cover, and check the unloader rod for free movement.
Repair or replace parts as necessary, and retest.
- If there is no vacuum at the inner fitting, check for vacuum at the choke opener and thermovalve A.
- If there is no vacuum at the outer fitting, check thermovalve A.
- Repair or replace as necessary.