Fuel System Components - Yanmar 4TNV98 Service Manual

Fuel System Components

Fuel is fed from the fuel tank into the fuel inlet of the
injection pump by the feed pump built into the
injection pump via the oil separator and fuel filter.
A filter is installed for fuel filtration. A filter with an oil
separator for water separation is also provided at
the bottom.
Pressure is applied to feed fuel into the fuel inlet by
the feed pump in order to feed fuel into the injection
pump chamber.
4TNV98 & 4TNE98 Diesel Engine
Figure 7-2
Although the fuel pressure in the pump chamber is
proportional to the pump revolution, excessive fuel
is returned to the suction system by the regulating
valve when the pressure exceeds the specified
value. The fuel is then sent to the plunger via the
fuel path in the distributor head. The plunger
applies high pressure to the fuel to feed it to the
nozzle and nozzle holder through the injection pipe.
The overflow valve above the injection pump
functions to maintain constant fuel temperature in
the pump chamber and return excessive fuel to the
fuel tank.
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Section 4. Fuel System