f. Gun interior. If thickened fuel has been fired, disassemble the gun. All parts should be cleaned of accumulations of dried fuel. Lubricate ([Par 49]) and reassemble. If liquid fuel has been fired, flush gun with clean gasoline. Disassemble only enough to lubricate. Reassemble.

Section XV
TROUBLE SHOOTING

57. PRECAUTIONS.

First, remove the ignition cylinder. Then, before disassembling, servicing, or repairing parts which may be under pressure, be sure to release the pressure. Remove fuel, when necessary.

58. FUEL LEAKS.

TroubleRemedy
a. Defective or damaged valve-diaphragm assembly.If leak is observed in valve grip, disassemble. ([Par 74]) If diaphragm is torn, or damaged in any other way, remove and replace. ([Par 75])
b. Defective threaded connections on fuel lines.Disconnect, using wrenches. If thread is stripped or badly damaged, replace the threaded part. If threads appear to be sound, clean them and reconnect. If leak is between tank coupling and tank connector or between hose and fuel-valve body, apply anti-seize compound before rescrewing. Tighten joint with wrenches.
c. Dirt or foreign matter on seats or threads.Clean parts carefully with cloth before reassembling.
d. Leak at nozzle.Adjust needle. ([Par 75 d]) If leak persists, either replace needle and barrel as a unit or use lapping compound on parts. Turn needle in seat until parts make a tight connection when seated. Remove lapping compound and reassemble.
e. Worn body of hose.Replace fuel-hose assembly. ([Par 73])
f. Leak at tank coupling.Remove and replace coupling washer if damaged. ([Par 70]) If hose nipple, tank end, is damaged, repair nipple ([Par 73 d]) or replace fuel-hose assembly.

59. SAFETY HEAD “BLOWS” (BREAKS).

TroubleRemedy
a. Defective safety head.Replace with new safety head. ([Par 69 b])
b. Defective pressure regulator.If replacement safety head also breaks, follow test procedure in Paragraph 56 b to determine whether pressure regulator needs adjustment or is defective.

60. CARRIER UNCOMFORTABLE.

TroubleRemedy
a. Cord becomes loose or breaks. Use only hard-braided seine cord furnished in service kit for replacements. Lace tightly as shown in [Figure 46], using slip-proof knots at ends.
b. Straps not adjusted to fit wearer.Adjust straps to fit each new wearer. Tank group must be high on back and snug on body. (Pars [19] and [71])
c. Carrier frame presses on wearer’s back.Cord is too loose. Tighten cord. Use slip-proof knots at ends.