Yamaha F50 Service Manual

							62Y3A114-2
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Hose routing4
Fuel and blowby hoses
1Blowby hose
2Hose (acceleration pump-to-carburetor)
3Fuel hose (fuel joint-to-fuel filter)
4Fuel hose (fuel filter-to-fuel pump)
5Fuel hose (fuel pump-to-carburetor)
6Hose (carburetor-to-carburetor)
Special service tools / Hose routing 
						

							FUELFuel system
4-362Y3A11
Cooling water hose
ÈModels with flushing device 
						

							62Y3A114-4
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— MEMO —
Hose routing 
						

							FUELFuel system
4-562Y3A11
Fuel line4 
						

							62Y3A114-6
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No. Part name Q’ty RemarksTightening torques
Stage N·mkgf·mft·lb
1 Fuel joint 1
2 Fuel filter 1 F50/F50A
3 Fuel filter 1 T50/FT50B, FT50C
4 Fuel pump 1
5Bolt 1 M6 ×
 25 mm
6 Seal 1
7 Fuel hose 1 Fuel joint-to-fuel filter
8 Clip 3
9Bolt 1 M8 ×
 14 mm
10 Nut 1
11 Bracket 1
12 Fuel hose 1 Fuel filter-to-fuel pump
13 Fuel hose 2 Fuel pump-to-carburetor
14 Clip 3
15 Bolt 2 M6 ×
 30 mm
16 O-ring 1
Not reusable
Fuel line 
						

							FUELFuel system
4-762Y3A11
Fuel filter and fuel pump4 
						

							62Y3A114-8
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È 
F50/F50A
É
 T50/FT50B, FT50C No. Part name Q’ty RemarksTightening torques
Stage N·mkgf·mft·lb
1 Fuel filter cup 1
2 O-ring 1
Not reusable
3 Fuel filter element 1
4 Body 1
5Float 1
6 Screw 4 M5 ×
 35 mm
7 Cover 1
8 Fuel pump body 2 1
9 Fuel pump body 1 1
10 Nut 4
11 Plunger 1
12 Spring 1
13 Spring 1
14 Pin 1
15 Diaphragm 1
16 Screw 2 M3 ×
 6 mm
17 Valve 2
18 Nut 2
19 Seal 1
Not reusable
20 Gasket 1Not reusable
Fuel filter and fuel pump 
						

							FUELFuel system
4-962Y3A11
Checking the fuel pump
1. Install the special service tool onto the
fuel pump as shown.
2. Apply the specified pressure to each fuel
pump port. 
3. If air flow is reversed, check the dia-
phragm for tears and the valves for
cracks. Replace if necessary.
CAUTION:
Do not over pressurize the fuel pump, oth-
erwise excessive pressure may cause air
leakage.
NOTE:
Make sure that air does not escape from
the opposite side of the fuel pump.
To eliminate any gaps between the fuel
pump valves and the fuel pump body 2, and
to ensure a better seal, make sure that the
inside of the fuel pump is moist with gaso-
line.
Disassembling the fuel pump
1. Disassemble the fuel pump as shown.
Pressure/vacuum tester: YB-35956-A
Vacuum/pressure pump gauge set:
90890-06756
Fuel pump pressure a
:
50 kPa (0.5 kgf/cm
2, 7.1 psi)
Fuel pump negative pressure b
:
30 kPa (0.3 kgf/cm
2, 4.3 psi) 
						

							62Y3A114-10
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2. Push down on the plunger and the dia-phragm, turn the fuel pump body 1  1
approximately 90 ° to a position where the
pin  2
 can be removed easily, and then
remove the pin.
3. Slowly let up on the plunger and dia- phragm, and then remove them.
Checking the diaphragm and valves
1. Check the diaphragm  1
 for tears and the
valves  2
 for cracks. Replace if neces-
sary.
Assembling the fuel pump
1. Align the plunger and diaphragm installa- tion holes  a
, and then install the plunger
into the diaphragm.  2. Push down on the plunger and the dia-
phragm, and then install the pin  1
.
3. Turn the fuel pump body 1  2
 approxi-
mately 90 °, and then push down on the
plunger several times to make sure that
the pin does not come out.
4. Assemble the cover  3
, gasket  4
, and
seal  5
 with the screws  6
, and then
install the fuel pump.
S62Y4120
1
2
S62Y4160
6
3
4
5
LTLT
572
Fuel filter and fuel pump 
						

							FUELFuel system
4-1162Y3A11
Carburetor unit4