5. FUEL SYSTEM MXU 500 IRS CARBURETOR DISASSEMBLY/INSPECTION/ ASSEMBLY DISASSEMBLY Remove the carburetor (refer to the "CARBURETOR REMOVAL/CHOKE INSPECTION/INSTALLATION" section in this chapter). Loosen the drain screw to drain the gasoline from the float chamber. · Keep sparks and flames away from the Fuel Drain Plug work area. · Drain gasoline into a clean container. · Do not loosen or tighten the painted bolts and screws of the carburetor. Loosening or tightening them can cause throttle and piston valve synchronization failure. Top Cap Remove the four screws and top cap . Spring Remove the spring and piston valve. Piston Valve 5-9