5. FUEL SYSTEM MXU 500 IRS Screws Control Shaft Washer DISASSEMBLY Remove the two screws on the retaining ring and then remove retaining ring. Remove the washer and control shaft. Retaining Ring Rubber Gasket Fuel Valve Body Remove the rubber gasket from the fuel valve body. INSPECTION Inspect the fuel valve body for dirt and clog. Clean if necessary. Replace the rubber gasket with new ones if they are damaged or deteriorated. Control Shaft O-ring Replace the O-ring with a new one if they are damaged or deteriorated. 5-5