Yanmar BY series, Service Manual

Page: 158 / 275

FUEL SYSTEM
BY Service Manual 6-29
Repair
Figure 6-40
5. Disconnect return fuel hose (Figure 6-40, (1))
from fuel tee.
Figure 6-41
6. Inspect O-ring (Figure 6-41, (1)) on each fitting.
If any O-ring is damaged, the entire return fuel
line
(Figure 6-41, (2)) must be replaced as an
assembly.
7. Assembly is in the reverse order from
disassembly.
8. Open fuel supply valve.
9. Bleed the fuel system. See Bleeding the Fuel
System on page 6-29.
10. Start engine and check for fuel leaks.
Bleeding the Fuel System
The fuel system needs to be bled under the
following conditions:
• Before starting the engine for the first time.
• After running out of fuel and fuel has been added
to the fuel tank.
• After fuel system maintenance such as changing
a fuel filter, draining the fuel filter / water
separator, or replacing a fuel system component.
The fuel feed pump is ECU-controlled and will
operate for only 10 seconds when the key switch is
turned ON and the engine is not running or being
started. For this reason, the key switch must be
repeatedly turned ON then OFF to sufficiently bleed
the fuel system.
1. Turn the key switch ON and leave ON for 10
seconds.
2. Turn key switch OFF for five seconds, then turn
key switch ON for 10 seconds.
3. Repeat steps 1 and 2 five more times.
Note: The engine may run rough and misfire
for a few seconds when first started until
any remaining air is purged from the fuel
system.
4. Attempt to start the engine. If the engine does
not start within a reasonable time, repeat steps
1 and 2 until the engine starts and runs.
000 3 6 88
(1)