TM-9-2320-272-24-2

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 2 OF 4

JUNE 1998

TM-9-2320-272-24-2 - Page 780 of 991

4-8. STARTING

TM 9-2320-272-24-2

NOTE

Coolant should not exceed 195°F (90°C) or drop below 175°F (79°C).

14.

15.

16.

17.

18.

Check engine idle speed. If idle speed is not 625 ± 25 rpm on M939/A1 series vehicles, perform steps

15 through 20. If idle speed is not 550-650 rpm on M939A2 series vehicles, perform steps 21

through 25.

Break special seal (2) and remove pipe plug (3) from governor spring pack cover (4). Discard special

seal (2).

Using spring pack adjusting tool, turn adjusting screw (5) in to increase idle speed; out to decrease

idle speed. Correct idle speed is 625 2 25 rpm.

Install pipe plug (3) on spring pack cover (4).

Thread wire of new special seal (2) through pipe plug (3) and two hex-head cover screws (1), and

twist wire of special seal (2) until secure.

4-98