a. Inspection of fuel tanks. Just before filling and charging, remove plugs ([Par 69 b]) and examine interior of fuel tanks to see whether they are clean and free from foreign matter. If not clean, flush with gasoline until clean.
b. Fuel level. When filling (Pars [37] through [40]), see that fuel reaches the same level in both tanks. If leveling does not occur, the tank connector may be clogged with foreign matter. If so, clean, as in a, above. After filling, wipe plug seats with a cloth before replacing plugs. Wipe any spilled fuel from weapon.
c. Pressure-tank valve. Before charging the tank group with air or nitrogen, open and close the pressure-tank valve several times by hand to be sure it operates freely. If it does not, adjust as described in Paragraph [66 d].
Fig 32. Testing pressure tank and valve, using 0-3,000-pound testing gage from service kit.
d. Testing for leaks in pressure system. After charging, and as few hours as possible before a mission, use an 0-3,000-pound gage furnished in service kit to test pressure. ([Fig 32]) To install gage, unscrew check-valve cap and screw gage in check-valve body. If pressure has fallen below that to which the tank was charged ([Par 32]), a leak is indicated. Remove gage, replace check-valve cap, and check for leaks at joints between pressure tank and valve and between tank valve and check valve. (A wrench should be used to tighten cap on check-valve body so as to avoid producing an additional leak.) Large leaks can be felt or heard. Small leaks can be detected by coating joints with soap-and-water solution. Bubbles indicate leaks. If a leak is revealed between pressure tank and pressure-tank valve, or between check valve and pressure-tank valve, replace all three as a unit. If tests do not show up the leak the tank may have been improperly charged. It should be recharged and then retested.
54. SERVICE WHEN FIRING.
a. Failure to ignite. Pull trigger repeatedly. If ignition cylinder still fails to ignite, dirt may be wedged in ignition head. Unscrew shield one-half turn. Screw it back, rapping shield with the hand while turning. This should dislodge foreign matter. Pull trigger again. Repeat procedure, if necessary.
b. Safety head “blows” (breaks). If safety head breaks, firing mission cannot be carried out. On return, have head replaced. ([Par 69]) Follow test procedure. ([Par 56 b])