Section VI. RADIO INTERFERENCE SUPPRESSION

Section VI. RADIO INTERFERENCE SUPPRESSION

accessories designed to ensure good electrical contact

3-26. General Methods

between various parts of the equipment, such as

Essentially, interference is suppressed by providing a

toothed lockwashers.

low-resistance path to ground stray currents. Methods

include shielding the ignition and high-frequency wires,

3-28.

Testing and Replacement of Suppression

grounding the frame with bonding straps, and using

Components

capacitors and resistors where necessary. For general

a. Correct faulty suppression by substituting new

information on radio interference sup-

suppression components until the defective ones are

found. Test engine generator regulator capacitor for

3-27. Interference Suppression Components

leaks and shorts on a capacitor tester; replace defective

a. Primary Suppression Components. The primary

capacitor. If test equipment is not available and

suppression components are those whose primary

interference is indicated, test by substitution.

function is to suppress radio interference.

These

Note In testing components by substitution, do not pull

components are as follows:

on cable or twist braided shielding in removing or

(1) Engine generator regulator capacitor.

replacing shielded ignition cables. Gently work cable

(2) Generator enclosure. The generator

from side to side and free the rubber seal. Do not use

is completely shielded by its housing, which is grounded

sharp metal tools to install rubber seals.

to the engine.

b. As many of the minor interference suppression

(3) Magneto bond strap.

components consist of IT (internal tooth), IET (internal-

(4) Shielded ignition wire.

external tooth) and ET (external tooth) lockwashers,

b. Secondary Suppression Components. The

always replace with the same type.

secondary components have radio interference

c. Be sure all bond straps are securely fastened.

suppression functions that are incidental and/ or

d. Tighten all fastening accessories.

secondary to their primary function. In the centrifugal

pump unit, these are mainly fastenings or fastening

Section VII. GAGES AND INSTRUMENTS

3-30. Cleaning, Inspection, and Replacement

3-29. General

a. Remove and install the level, pressure, and

Gages and instruments are located on the instrument

temperature gages as shown by figure 3-6.

panel box, and the fuel tank. They must be replaced

Remove and install the tachometer drive

when they become inoperative or give incorrect

assembly as shown by figure 3-7.

readings during normal operation. Inspect all wiring

c. Refer to figure 3-6 and remove and install the

removed during the replacement; inspect for cracked or

tachometer-hourmeter.

frayed insulation, and replace any defective leads. Also

d. Refer to figure 3-6 and remove and install the

check oil-pressure and water-temperature sending units

starting switches.

(para 3-53). Tag and remove the necessary lines, leads

e. Clean and inspect for corrosion, breaks or other

and cable before removing any gage or instrument.

defects.

Section VIII. PUMPING ASSEMBLY AND COUPLING

3-31. Inspection

deficiencies as loose or missing bolts or nuts, and bent,

Make a general visual examination of the pumping

cracked, or broken parts.

assembly and coupling for such

3-16