DE-CARBONING PROCEDURE
This procedure is required every 100 hours or annually for MFE 55 outboards operated using heavy fuels, including JP5, JP8, Jet A, or kero sene.
If the outboard has been operated on an emer gency fuel, such as diesel, the de-carbon proce dure must be performed immediately after return from the mission.
IMPORTANT: Diesel is an emergency fuel ONLY. If diesel must be used, the fuel selector switch should be in the Heavy Fuel position.
For maximum benefit, the outboard should be run on unleaded gasoline during this procedure if possible.
Outboard should be on the boat and in the water. If outboard cannot be run in the water, make sure to supply adequate cooling water.
DO NOT run the engine indoors or without adequate ventilation or permit exhaust fumes to accumulate in confined areas. Engine exhaust contains carbon monoxide which, if inhaled, can cause serious brain damage or death.
To prevent injury from contact with rotating propeller; remove the propeller before de-carbon procedure (MRL).
DO NOT run outboard without a water sup- ply to the outboard’s cooling system. Cooling system and/or powerhead damage could occur.
Remove air silencer.
Set the fuel selector switch to the gasoline position and run the outboard on gasoline during the de-carboning procedure.
Start and run outboard long enough to reach nor mal operating temperature.
Set engine speed to approximately 1500 RPM.
Spray the entire contents of a can of Engine Tuner, P/N 777185, into the throttle body. Do not let the engine stall until the can is empty.

- Throttle body
STOP engine and allow Engine Tuner to soak in powerhead for a minimum of 8 hours to 16 hours maximum.
DO NOT allow Engine Tuner to stay in powerhead for more than 16 hours.
Extended exposure can damage internal engine parts.
Restart engine and run at 1500 RPM for 15 minutes.
Next, run outboard on boat, at high speed, for 30 to 60 minutes. Boat should be on plane and out board should be running at least 2500 RPM.
If outboard will not run at high RPM, make sure that spark plugs are not fouled. Replace spark plugs if necessary. Refer to SPARK PLUGS on p. 63.
