Section X. MAINTENANCE OF NON-ELECTRICAL GAGES

or binding dial pointers, damaged terminals,

evidence of entry of moisture, and other damage.

Replace damaged gages and meters.

(3) Check all switches for cracked cases,

difficult operation, lack of positive switch action,

and other damage. When you check the switches

for continuity, use a multimeter or test lamp.

Replace defective switches.

( 4 ) Inspect the magneto stop switch for

cracks, loose or damaged terminals, and other

damage. Continuity should not exist when the

switch is in the run position; continuity should exist

when the switch is in the stop position. Replace a

damaged or inoperative magneto switch.

(5) Inspect the hoses for cuts, abrasions,

l e a k s , damaged threads, and other damage.

Replace damaged hoses.

(6) Check the operation of the oil pressure

safety switch by checking continuity across the

terminals while you apply air pressure to the

pressure port. Start with the switch in the reset

position (with the spring clip inserted under the

recess in the housing). No continuity must exist at

this time. Slowly apply air pressure. When ap-

proximately 1 psi pressure is applied, the spring

clip must disengage from the housing, with no

continuity being maintained through the switch.

Increase pressure to maximum 5 psi, then reduce

pressure. W h e n y o u l o w e r p r e s s u r e t o a p -

proximately 1 psi, continuity must be established

and must remain when the pressure is further

reduced to zero. Replace the switch if it fails to

perform as indicated.

b. Cleaning and Inspection.

( 7 ) Inspect all other p a r t s f o r c r a c k s ,

WARNING

distortion, damaged threads, and other damage;

Clean all parts in a well-ventilated area.

replace damaged parts.

Avoid inhalation of solvent fumes and

c. Reassembly and Installation.

prolonged exposure of the skin to

(1) Reassemble and install the controls, in-

cleaning solvent. Wash exposed skin

d i c a t o r s , and gages in the opposite order of

thoroughly.

removal; refer to figure 4-13.

(1) Clean all parts by wiping them with a

(2) Connect the electrical leads to the properly

cloth dampened lightly with cleaning solvent (fed.

tagged components. Refer to figure 1-3, wiring

spec. P-D-680). You must be careful to prevent the

diagram.

solvent from entering the interior of the com-

(3) After installation, start the engine and

ponents.

check that you have proper operation of switches

(2) Inspect all meters and gages for cracked

and gages. Check thoroughly for leaks.

dial glass, defaced or illegible dial marking, sticking

Section X. MAINTENANCE OF NON-ELECTRICAL GAGES

each gage to prevent momentary pressure surges

4-29. Description

from damaging the re!ated gage.

a. Three large gages on the engine control panel

b. The tachometer-hourmeter mounted on the

k e e p you informed of the pump suction and

control panel is driven by a flexible drive shaft

discharge pressures, and the engine vacuum. They

which connects to a drive adapter on the governor.

are connected to their related system by hoses and

fittings. Each system incorporates a dampener at

4-27