Installation Instructions

B1700·B2100·B2400 WSM, 11770
(3) Fuel Feed Pump
1 ENGINE
Filtered fuel is fed to the injection pump by the
fuel lift pump. The fuel lift pump operates as shown
in the figure. Power
is applied to the tappet by an
eccentric movement on the fuel camshaft. As the
fuel camshaft rotates, the eccentric movement causes
the tappet to move up and down. The tappet is
linked to a flexible diaphragm (4) via the pull rod.
When
the diaphragm is pulled down, a low
vacuum or low pressure area is created above the
diaphragm. This causes atmospheric pressure in the
fuel tank
to force fuel into the fuel lift pump. The
inlet valve (1) opens to admit fuel into the chamber
(3).
When the diaphragm is pushed up, pressure is
created in the area above the diaphragm. This
pressure
closes the inlet valve and opens the outlet
valve (2), forcing fuel from the pump through the
fuel pipe to the injection pump.
(A)
(B)
B177F105
[AI Inlet Stroke
(a) From
Fuel Filter
(1) Inlet Valve
(2) Outlet Valve
[01 Discharge Stroke
(b)
To Injection Pump
(3) Chamber
(4) Diaphragm
1-M13