Idle Speed: Adjustments

4-140

1. Place transmission into Neutral or Park.
2. Install a suitable tachometer onto engine as per manufacturer's instructions.
3. Start and allow engine to reach normal operating temperature.
4. Place A/C-Heat selector switch to OFF position, if equipped.
5. Check curb idle speed. If curb idle speed obtained is not as specified, turn curb idle speed adjusting screw until specified speed is obtained. See image with applicable components.

YFA-i V Non-FB w/TSP-Curb Idle RPM:

W/YFA feedback carburetor

YFA-1V Non-FB w/TSP and Idle Tracking Switch-Curb Idle RPM:

W/YFA feedback carburetor, TSP & Idle tracking switch

YFA-1V Non-FB w/TSP and VOTM-Curb Idle RPM:

W/YFA feedback carburetor, TSP & VOTM

YFA-1V Non-FB with TSP/VOTM Idle Tracking Switch-Curb Idle RPM:

W/YFA feedback carburetor, TSP, VOTM & ITS

Fig. 6 Curb idle speed adjust. 4-140 engine W/6149 feedback carburetor:

4-140 HIGH SWIRL COMBUSTION (HSC) ENGINE W/6149 FEEDBACK CARBURETOR

1. Place transmission into Neutral or Park.
2. Disconnect and plug throttle kicker vacuum line.
3. Install a suitable tachometer onto engine as per manufacturer's instructions.
4. Start and allow engine to reach normal operating temperature. Ensure cooling fan is On.
5. Place A/C selector switch to OFF position.
6. Using a suitable jumper wire, activate cooling fan by grounding control wire.
7. Check curb idle speed obtained. If curb idle speed obtained is not as specified, turn idle speed adjusting screw until specified speed is obtained, Fig. 6.