Fuel Line; Reducing The Fuel Pressure; Measuring The Fuel Pressure - Yamaha F150B Service Manual

Fuel line

Reducing the fuel pressure

Always reduce the fuel pressure in the
high-pressure fuel line before servicing
the line or the vapor separator. If the fuel
pressure is not released, pressurized fuel
may spray out.
1. Remove the cap a.
2. Cover the pressure check valve a of the
fuel rail with a rag, and then press in the
pressure check valve a using a flathead
screwdriver to release the fuel pressure.
a
3. Install the cap a.

Measuring the fuel pressure

1. Reduce the fuel pressure.
2. Remove the cap a.
3. Connect the special service tool b to the
pressure check valve a. WARNING!
Gently screw in the gauge until it is
firmly connected to prevent fuel from
leaking out.
a
b
a
a
c
b
Hose routing / Fuel line
Fuel pressure gauge b:
90890-06786
4. Turn the engine start switch to "ON," and
then measure the fuel pressure within 3
seconds. WARNING! Make sure that
the drain screw c is tightened
securely, before measuring the fuel
pressure.
Fuel pressure (reference data):
300.0 kPa (3.00 kgf/cm
TIP:
The fuel pressure decreases after 3 seconds
later when the engine start switch is turned to
"ON."
5. Start the engine and warm up, and then
measure the fuel pressure at the stable
idle condition of 650–750 r/min. If below
specification, check the high-pressure
fuel line and the vapor separator.
Fuel pressure (reference data):
260.0 kPa (2.60 kgf/cm
at engine idle speed
6. Turn the engine start switch to "OFF."
7. Disconnect the special service tool b,
and then install
WARNING! Before disconnecting the
special service tool b, cover the pres-
sure check valve a with clean and dry
rag, otherwise pressurized fuel may
spray out.
8. After measuring the fuel pressure, cover
the end of the hose with a clean and dry
rag, point the hose downward. And then
loosen the drain screw c to drain the
remaining fuel from the hose and gauge.
WARNING! When storing the fuel
pressure gauge, make sure that the
drain screw c is tightened securely.
Fuel line
0
1
2
2
, 43.5 psi)
3
4
5
2 , 37.7 psi)
6
7
a.
the cap
8
9
10
A
6-4