Idle Up Control Valve: Testing and Inspection

1. Start engine and warm-up to normal operating temperature.
2. Check idle speed.

Idle Speed: 650 ± 50 rpm

3. Disconnect vacuum hose from throttle opener and plug hose end.

Checking Throttle Opener Adjustment:

4. Maintain engine rpm at 2,500 rpm with throttle valve.
5. Release throttle valve suddenly and check throttle opener setting speed.

Setting Speed: 1,300 - 1,500 rpm

NOTE: With Cooling Fan OFF

6. If not within specifications, adjust to proper speed by lengthening or shortening the plunger rod.

Adjusting Throttle Opener:

7. Reconnect the vacuum hose and ensure that the throttle opener plunger is pulled back, allowing the idle to return to normal.

Reconnecting Vacuum Hose To Throttle Opener:

8. If diaphragm does not retract, use a handheld vacuum pump to check for a ruptured diaphragm.
9. If a problem is found, replace the throttle opener.
10. If diaphragm is OK, check vacuum hose or throttle body for a blockage.
11. If a blockage is indicated, refer to THROTTLE BODY for proper cleaning procedure.