FUNCTION OF MAJOR COMPONENTS
Name of Component
Function
Fuel Filter / Water Sepa-
rator (not supplied by
Yanmar)
Removes dirt and water from the fuel. The filter element should be replaced pe-
riodically. See Replacing Fuel Filter / Water Separator Element on page 52.
The water separator should be drained periodically. See Draining the Fuel / Wa-
Fuel Fine Filter
Removes extremely fine contaminants from fuel prior to entering fuel injection
system.
Fuel Feed Pump
Pumps fuel from the tank to the fuel injection system.
Engine Oil Fill Port
To add engine oil.
Engine Oil Filter
Filters fine metal fragments and carbon from the engine oil. Filtered engine oil is
distributed to the engine's moving parts. The filter is a cartridge type and the
element should be replaced periodically. See Changing the Engine Oil and Re-
placing the Engine Oil Filter on page 48.
Coolant System
There are two cooling systems: 1) closed cooling with coolant and 2) seawater.
The engine is cooled by the closed cooling system. The closed system coolant
is cooled by seawater using a heat exchanger. The seawater also cools the ma-
rine gear or power steering oil, and the combustion intake air through cooler(s)
in an open circuit.
Closed Cooling Circula-
tion Pump
The centrifugal coolant pump circulates coolant inside the engine. The circulating
pump is driven by a poly V-belt.
Seawater Pump
Pumps seawater from outside vessel to the engine. The seawater pump is belt-
driven and has a replaceable rubber impeller. Avoid impeller damage, do not
operate it without seawater.
Coolant Fill Cap
When the coolant temperature rises, the pressure inside the heat exchanger
increases, causing the pressure valve in the filler cap to open, forcing hot water
and steam through a rubber hose to the coolant recovery tank. When the engine
becomes cool and the pressure inside the coolant recovery tank drops, the vac-
uum valve in the filler cap opens and the coolant in the coolant recovery tank
returns to the heat exchanger through the hose and filler cap. This minimizes
coolant consumption.
Coolant Recovery Tank
The coolant fill cap valve releases vapor and hot water overflow to the coolant
recovery tank. When the engine stops and the coolant cools, the pressure in the
heat exchanger drops. The fill cap valve then opens to send coolant back from
the coolant recovery tank. This minimizes coolant consumption. The closed
cooling system coolant level can easily be checked and refilled in this tank.
Oil Cooler - Engine
A heat exchanger that cools high temperature engine oil using engine coolant.
Oil Cooler - Hydraulic
A heat exchanger that cools the marine gear oil or power steering fluid using
seawater.
Turbocharger
The turbocharger pressurizes the air coming into the engine. It is powered by a
turbine that is driven by exhaust gases.
Air Filter
The air filter removes dirt from the intake combustion air reducing engine wear.
Nameplates
Nameplates are provided on the engine and the marine gear and have the model,
serial number and other data.
PRODUCT OVERVIEW
16
BY Series Operation Manual
© 2008 Yanmar Marine International