THEORY OF OPERATION (Contd)
FUNCTION OF RAW WATER COOLING SYSTEM
The port and starboard engines have their own separate raw water cooling systems. The raw water cooling
system cools the transmission oil and exhaust pipes and allows for raw water to flush the keel cooler area.
High-pressure raw water supplied from the hydrojets circulates using two paths:
1. Path One: High pressure raw water from hydrojet is circulated through raw water strainer supply hose,
into raw water strainer, raw water transmission oil cooler supply hose, transmission oil cooler,
wet exhaust supply hose, and wet exhaust pipe elbow, and overboard through exhaust port.
2. Path Two: Raw water supplied from hydrojet is circulated through keel cooler raw water flush hose, into
keel cooler connection, and out to raw water underneath hull. This prevents still water heat-
up near keel cooler.
FUNCTION OF THE FUEL SYSTEM
Each engine has its own fuel system except that fuel is drawn from a common fuel tank. The fuel systems
are identical. Fuel gravity feeds from fuel tank to main shut-off valve. From this point, fuel is drawn
through the system using the fuel pump. Fuel splits into two separate fuel lines: one for port and the other
Once fuel has reached the starboard fuel shut-off valve and valve is open, fuel flows to fuel water separator,
lubricity fuel filter, fuel pump, fuel filter, fuel injector pump, fuel high-pressure supply lines, and fuel
injectors. Excess fuel not used by fuel injectors will flow into the low-pressure fuel return line and back into
fuel tank. The fuel tank vent line is routed through port side battery compartment and upward along the
port side of the boat.
FUNCTION OF THE AIR INTAKE AND EXHAUST SYSTEM
Each engine is equipped with a breathing tube located on the port side of the engine block. A flexible tube
from each engine is routed to a filter bracket and is connected to the breather filter. Noncondensed vapors
are vented into the engine compartment.
The port and the starboard engines have individual air intake exhaust systems. The systems are identical
except that the port engine discharges exhaust gases to port side and the starboard engine discharges
exhaust gases to starboard side. Both port and starboard exhaust systems are cooled by raw water from the
FUNCTION OF THE FIRE SUPPRESSION SYSTEM
The engine compartment fire suppression system consists of a single fire extinguisher automatically
activated when the temperature sensor on the top of the bottle reaches 175 F (79.4 C). During discharge,
shut down engines as soon as possible so extinguishing agent (FM200) can flood engine compartment.
FM200 (CF3CHFCF3) extinguishing agent requires no cleanup.
If fire extinguisher has been discharged, report fire extinguisher discharge to supervisor.