Components Of Fuel Feed System; Vapor Separator - TOHATSU MFS 25D Service Manual

Fuel System (Fuel Injection)

6. Components of Fuel Feed System

1) Fuel Pump [Low Pressure Mechanical Pump]
The fuel pump is a diaphragm pump that is operated mechanically by the camshaft.
a IN: Fuel from Filter/Tank
b OUT: Fuel Outlet to Vapor Separator

2) Vapor Separator

Vapor separator feeds only liquid fuel for internal fuel feed pump (FFP) 1 (electrical high pressure pump). Fuel that
is fed from fuel pump (low pressure mechanical pump) is sent to upper part of vapor separator, where it is controlled
with needle valve 2/float 3 assy. Removes trash and fuel filter (suction side) 4 Fuel filter (discharge side) 5 when
passing through the Fuel Feed Pump (FFP). High pressure fuel from fuel feed pump (FFP) is fed to fuel rail and
fuel injector. Excessive fuel is returned to the chamber by a fuel regulator 6 that is built into the vapor separator. In
addition, a fuel cooler is mounted in the vapor separator to suppress an increase in the fuel temperature.
4-28
OUT
IN
a
Excessive fuel
Normal fuel
b
1 Fuel Feed Pump (FFP)
2 Needle Valve
3 Float
4 Fuel Filter (suction side)
5 Fuel Filter (discharge side)
6 Fuel Regulator
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