Installation manual

ManualsBrandsMercury ManualsBoat200 OptiMax DTS

1-61

90-898305

Oil

Oil in this engine is not mixed with the fuel before entering the combustion

chamber. Oil is stored inside a standard remote oil reservoir. Crankcase

pressure will force oil from the remote oil reservoir into the oil storage tank on

the side of the powerhead. Oil will flow from the oil storage tank into the oil

pump. The oil pump is a solenoid design. It is activated by the ECM and

includes pistons with corresponding discharge ports. The oil pump is mounted

directly onto the powerhead. Each cylinder is lubricated by one of the

discharge ports. The oil is discharged into the crankcase in front of the reed

blocks or crankcase cover. The seventh passage connects to the hose that

leads to the air compressor for lubrication. Excess oil from the compressor

returns into the plenum and is ingested through the crankcase. Later models

have check valves inside the cylinder oil circuits. These check valves prevent

evacuation of the oil hoses under certain operating conditions.

The ECM will change the discharge rate of the oil pump, depending upon

engine demand. The ECM will also pulse the pump on initial start up to fill the

oil passages eliminating the need to bleed the oil system. The ECM provides

additional oil for break in, as determined by its internal clock. The oil ratio

ranges from 300-400:1 at idle to 60:1 at WOT. A OptiMax engine will use less

oil than a non-OptiMax engine.

Electrical

The electrical system consists of the ECM, crank position sensor (flywheel

speed & crankshaft position), throttle position sensor (TPS), MAP sensor,

engine temperature sensor, ignition coils, water pressure sensor (not used on

all models) and injectors (fuel & direct). The engine requires a battery to start

(i.e. the ignition and injection will not occur if the battery is dead). The system

will run off of the alternator.

Operation

The operation of the system happens in milliseconds (ms); exact timing is

critical for engine performance. As the crankshaft rotates, air is drawn into the

crankcase through the throttle shutters, into the plenum, and through the reed

valves. As the piston nears bottom-dead-center, air from the crankcase is

forced through the transfer system into the cylinder. As the crankshaft

continues to rotate the exhaust and intake ports close. With these ports

closed, fuel can be injected into the cylinder. The ECM will receive a signal

from the throttle position sensor (TPS), engine temperature sensor (TS) and

the crank position sensor (flywheel speed and position sensor). With this

information the ECM refers to the fuel calibration (maps) to determine when to

activate (open and close) the injectors and fire the ignition coils. With the

piston in the correct position, the ECM opens the fuel injector, approximately

90 psi fuel is discharged into a machined cavity inside the air chamber of the

air/fuel rail. This mixes the fuel with the air charge. Next the direct injector will

open, discharging the air/fuel mixture into the combustion chamber. The direct

injector directs the mixture at the bowl located in top of the piston. The piston’s

bowl directs the air/fuel mixture into the center of the combustion chamber.

This air fuel mixture is then ignited by the spark plug.

Notes

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