Section XIII. MAINTENANCE OF CONTROLS AND INSTRUMENTS

(3) Check the armature for free rotation. There

(5) Replace the starting motor if it is worn,

must be no catching, binding, or scraping as the

damaged, or inoperative.

armature is rotated.

c. Installation.

(4) To check the starting motor solenoid, apply

(1) Position the starting motor (3, fig. 4-26)

24 vdc between the BAT terminal of the solenoid and

with its assembled solenoid switch on the flywheel

the switch (S) terminal. This will advance the starter

housing of the engine; secure with three cap screws (1)

drive to the engaged position. With the drive advanced

and lock washers (2).

and power still applied, check continuity between the

(2)

If necessary, refer to figure 1-4 for

BAT and motor (M) terminals Continuity must exist.

connection information.

Break the circuit to the terminals. The drive must retract

(3) Attempt to start the engine as directed in

fully, and the circuit between the BAT and motor (M)

paragraph 2-3. The starting motor must crank the

terminals must break.

engine

freely

and

easily.

Section XIII. MAINTENANCE OF CONTROLS AND INSTRUMENTS

4-43. Description

The engine controls and instruments are

e. The starter disengage relay, mounted on the

mounted on the control panel which is part of the dash

control panel, opens the circuit to the starter solenoid

assembly of the engine. Refer to figure 1-4 for the

switch to deenergize the start circuit immediately when

wiring diagram showing the electrical connections

the engine starts, and prevents the operation of the

between the engine and controls. The function of the

starting motor at any time while the engine is running.

controls and instruments is described in table 2-1.

This protects the starting motor from damage which

b. The engine has three protective devices which

could be caused by accidental operation of the starter

will shut down the engine under certain conditions which

push-button while the engine is running. The operating

could damage the engine. These conditions are high

coil of the relay is connected to alternator output so that

coolant temperature, low oil pressure, and engine

the start circuit is held open whenever there is alternator

overspeed. In each of these emergency conditions, the

output.

engine shutdown is accomplished by grounding the

4-44.

Control Panel Engine Controls and

primary of the magneto to prevent the engine ignition

Instruments

system from operating.

c. Two large gages on the engine control panel

a. Removal and Disassembly.

CAUTION

indicate the suction and discharge pressures of their

related systems. They are connected to the pump by

Disconnect the battery cables from the

lines and fittings, and each system incorporates a valve

positive

battery

terminals

before

to disconnect the gage from the system if desired. A

disconnecting any leads to the engine

dampener in the system at each gage prevents

controls and instruments.

This will

momentary pressure surges from damaging the related

prevent shorts which could damage the

gage.

alternator, voltage regulator, and other

d. The tachometer-hourmeter mounted on the

parts.

control panel is driven by a flexible drive shaft which

(1) Disconnect the electrical leads from the

connects to a drive adapter on the overspeed governor

engine controls and instruments on the control panel.

arm. The drive adapter meshes with a threaded portion

Tag leads to facilitate reassembly.

of the overspeed governor drive shaft, providing the

(2)

Remove and disassemble the engine

rotational force necessary to operate the tachometer-

controls and instruments from the control panel as

hourmeter.

shown in figure 4-27.

4-45