1971 Johnson 125HP outboards Service Manual, Page 23Get this manual
cRemove low-speed needle valves from carburetorSee Figure 3-10Note black needle valve retainer on port side; white retainer on starboard sidedRemove four screws attaching float chamber to carburetor bodyRemove float chamber and gasketRemove nylon hinge pin to permit removal of float and float arm assemblySee Figure 3-11eRemove float valve, float valve seat, and gasket assembly from carburetor bodyCLEANING, INSPECTION AND REPAIR
GENERAL INSTRUCTIONS Clean all parts, except float and float valve, in solvent and blow dryDO NOT dry parts with cloth as lint may cause trouble in the reassembled carburetorBe sure all particles of gaskets are removed from gasket surfacesFlush all passages in the carburetor body with solvent and remove any gummy deposits with OMC Accessory Engine CleanerCertain solvents will not remove this gum which accumulates particularly in the float chamber and on needle valvesFLOAT AND NEEDLE VALVE aInspect float and arm for wear or damageIf the float is damaged, discard it and install new oneCheck float arm wear in the hinge pin and needle valve contact areasReplace if necessarybInspect the inlet needle valve for grooves, nicks, or wearIf any are found, replace float valve assemblySee Figure 3-12Gum or varnish on the needle valve must be removed with OMC Accessory Engine CleanerDO NOT attempt to alter the shape of the needle valvescCheck the needle valve seats with magnifying glass; if seat is nicked, scratched, or worn out-of-round, it will not give satisfactory serviceSee Figure 3-13The valve seat and needle are matched set; if either is worn, both parts must be replacedUse new gasket when reinstalling the needle seat