(2) _Straps._ Adjust straps to fit each firer, moving slides on straps as necessary. Straps must fit snugly to prevent shifting of load and to keep tank group high on firer’s back. Lower body straps may be fastened in second pair from the bottom of carrier eyelets to conform to firer’s physique. Pins, which hold top ends of shoulder straps to steel support between the fuel tanks, may be moved to any two of the three holes so as to provide the best balance in the load. _e. Maintenance of carrier._ Keep carrier dry and clean. If flame thrower becomes wet or muddy, clean and dry carrier thoroughly. Store in a dry place. If rotted, mildewed, or damaged, replace affected parts. If cord frays or breaks, use special seine cord from service kit as replacement. Section XVII GUN GROUP 72. GENERAL The gun group consists of the fuel-hose assembly and the gun. The gun includes the fuel valve, which controls the ejection of fuel, and the ignition head, which ignites the fuel. 73. FUEL-HOSE ASSEMBLY. _a. Description and functioning._ (Fig 47) Hose, fuel, flame thrower, M1, assembly, provides a flexible connection between the fuel tanks and the gun. (1) _Hose._ Made of synthetic rubber and reinforced with a cover of metal wire and cotton braid, the hose resists the action of gasoline and oil, and withstands a pressure of approximately 1,000 pounds per square inch. Its inside diameter is 7/8 inch; its outside diameter is approximately 1-1/4 inches. (2) _Nipples._ The hose nipple, tank end, connects the hose to the tank coupling on the tank group. The hose nipple, gun end, is a threaded connector between the other end of the hose and the fuel-valve body. _b. Removal of fuel-hose assembly._ Remove the hose from the gun only when necessary for maintenance. The threads in the fuel-valve body will be damaged by frequent screwing and unscrewing of the hose because the body is a lightweight aluminum casting. Fuel hose is replaced as a unit and is not disassembled in the second echelon. To disconnect from tank group, see Paragraph 70 _b_. _c. Installation of fuel-hose assembly._ (1) To install in tank group, see Paragraph 70 _c_. (2) To install in gun, apply anti-seize compound (from service kit) lightly to threads and screw hose in fuel-valve body by hand. Use wrench only enough to make a secure connection. _d. Maintenance of fuel-hose assembly._ If the hose nipple, tank end, is badly nicked and does not provide a tight connection with a new coupling washer (Par 70): (1) File the end surface, being careful to keep the surface at a right angle to the sides of the nipple. (2) Couple hose nipple, tank end, to tank coupling. If coupling closes very easily, indicating washer is not being compressed, replace the washer and recouple. If coupling still closes too freely, the nipple has been filed too short, and the fuel-hose assembly should be replaced as a unit. 74. VALVE GRIP.