1999 "EE" 90, 115 FFI, 150, 175 V4, V6 FFI Outboards Service Manual, P/N 787024, Page 40Get this manual
7Inspect propeller shaft seals for evidence of leakageReplace if necessary 8Drain and refill gearcaseLubricate all components of engineSee Lubrication, this section9Check propeller conditionReplace if damaged10Retorque all screws and nuts to specifications11Run engine in test tank with correct test propellerCheck cooling system operation12To remove carbon deposits from combustion chambers and pistons, inject CIVIC Engine TunerLet tuner soak in engine between three and sixteen hoursAfter soaking, run engine at fast idle (1500 RPM) for at least 15 minutes at normal operating temperature INotel
During engine operation, carbon can build up on internal powerhead components, eventually causing piston rings to "stick Adding CIVIC Carbon Guard fuel additive to every tank of fuel is your best protection against such buildup and the resulting mechanical problemsIf CIVIC Carbon Guard is not used consistently in the fuel, CIVIC Engine Tuner should be applied every 50 operating hours13Check engine operation by verifying minimum test propeller RPMRefer to Engine Specifications, this section