Yanmar 1GM User Manual page 148

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be operating properly to adequately protect the fuel injec-
tion system . Failure to maintain fuel fillers and use clean
fuel can result in engine stoppage and expensive replace-
ment or repair of the injection pump or injectors.
Fuel Transfer Pump
The fuel transfer pump (A, Figure 9) moves fuel from
the fuel lank to the fuel injection pump. The pump is nec-
essary when the fuel tank is lower than the fuel injection
pump. A primer lever on the side ofthe trans fer pump per-
mits manual operation of the fuel pump d iaphragm.
Priming or bleeding the fuel system requires operation of
the primer lever so fuel flows to the injection system with
the eng ine slopped.
FUEL I."'JECT IOI\ SYSTE:vJ BLEEIlING
Air in the fuel system can cause rough engine operation
or stoppage. Bleeding purges air from the system . Bleed
the system anytime fuel line connections are discon nected
or fuel components are removed. To ensu re all a ir is re-
moved, perform the complete bleeding procedure de-
scribed in the following steps:
I. Open the bleed screw on the fuel filter (Figure 10).
Make sure the fuel valve on the fuel tank is open.
NOTE
Be prepared to contain and
IVI/)e
up expelled
file!.
2. Operate the priming lever
(8,
Figure 9) on the fuel
transfer pump while observing the fuel expelled from the
bleed screw ho le. Continue to operate the priming lever
until air-free fue l is expelled, then close the air bleed
screw.
C H A PTE R SEVEN
3. Open the air bleed screw (Figure II) on the fuel injec-
tion pump.
4 . O perate the priming lever (8, Figure 9) on the fuel
transfer pump while observing the fuel expelled from the
ble ed screw hole. Continue to operate the pri ming lever
until air-free fuel is expelled , then close the air bleed
screw.