Kubota WSM L3560, Workshop Manual

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ENGINE
L3560, L4060, L4760, L5060, L5460, L6060, WSM
1-M8
Feed Pump
The feed pump (1) is installed after the fuel cooler
and has a function of suctioning fuel from the fuel tank
and pressure feeding it through a filter and to the supply
pump.
Also, the feed pump is provided with a priming pump
(2). This is for air removal through the supply pump
through manual operation of the priming pump.

Operating
During the up stroke, the piston (5) is pushed up by
the fuel cam (8) via the tappet (7) and push rod (13). As
a result, the pressure in the inner chamber (9) rises, the
suction side check valve (3) closes and the discharge
side check valve (10) opens. On the other hand, the
pressure in the outer chamber (12) is lowered so the
suction side check valve (6) opens and discharge side
check valve (11) closes.
During the down stroke the piston is lowered by a
piston spring (4) and the pressure in the inner chamber
is lowered so the suction side check valve opens and
discharge side check valve closes. On the other hand,
the pressure in the outer chamber rises so the suction
side check valve closes and discharge side check valve
opens.
9Y1210824ENM0011US0
(1) Feed Pump
(2) Supply Pump
(3) Suction Side Check Valve
(4) Piston Spring
(5) Piston
(6) Suction Side Check Valve
(7) Tappet
(8) Fuel Cam
(9) Inner Chamber
(10) Discharge Side Check Valve
(11) Discharge Side Check Valve
(12) Outer Chamber
(13) Push Rod
(A) Suction Side
(B) Discharge Side
[A] Up Stroke
[B] Down Stroke
KiSC issued 03, 2016 A