Yamaha F50 Service Manual

							62Y3A118-20
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Checking the fuse
1. Check the fuse and fuse holder for conti-
nuity. Replace if there is no continuity.
Checking the wiring harness 
(10 pins)
1. Check the wiring harness for continuity.
Replace if there is no continuity.
Checking the neutral switch
1. Check the neutral switch for continuity.
Replace if there is no continuity.
Checking the starter relay
1. Connect the digital circuit tester leads to
the starter relay terminals.
2. Connect the brown (Br) lead to the posi-
tive battery terminal.
3. Connect the black (B) lead to the nega-
tive battery terminal.4. Check for continuity between the starter
relay terminals. Replace if there is no
continuity.
5. Check that there is no continuity between
the starter relay terminals after discon-
necting the brown or black lead. Replace
if there is continuity.
Lead color
Brown (Br)
Brown (Br)
Free
Push
Starting system 
						

							ELECElectrical systems
–+
8-2162Y3A11
Starter motor8 
						

							62Y3A118-22
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No. Part name Q’ty RemarksTightening torques
Stage N·mkgf·mft·lb
1 Clip 1
2 Pinion stopper 1
3Spring 1
4 Starter motor pinion 1
5 Upper bracket 1
6 O-ring 1
Not reusable
7 Washer 1 1
8Shim—As required
9 Washer 2 1
10 Armature 1
11 Stator 1
12 O-ring 1
Not reusable
13 Brush holder assembly 1
14 Brush set 1
15 O-ring 1
Not reusable
16 Washer 1
17 Spring washer 1
18 Nut 1 9 0.9 6.5
19 Lower bracket 1
20 Screw 2 M4 ×
 12 mm
21 Bolt 2 M5 ×
 125 mm
Starter motor 
						

							ELECElectrical systems
–+
8-2362Y3A11
Removing the starter motor pinion
1. Slide the pinion stopper 1
 down as
shown, and then remove the clip 2
.
Checking the starter motor pinion
1. Check the pinion teeth for cracks or
wear. Replace if necessary.
2. Check for smooth operation. Replace if
necessary.
NOTE:
Turn the pinion clockwise to check that it
operates smoothly and turn it counterclock-
wise to check that it locks.
Checking the armature
1. Check the armature axial free play.
Replace the washers and shim(s) 3
 if
out of specification.2. Check the commutator for dirt. Clean
with #600 grid sandpaper and com-
pressed air if necessary. 
3. Measure the commutator diameter.
Replace the armature if out of specifica-
tion.
Dial gauge 1
: YU-03097
Dial gauge set 1
: 90890-01252
Magnetic flexible stand 2
: YU-34481
Magnet base 2
: 90890-06705
Free play limit: 0.6 mm (0.024 in)
Diameter limit: 31.0 mm (1.22 in)  
						

							62Y3A118-24
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4. Measure the commutator undercut a
.
Replace the armature if out of specifica-
tion.
5. Check the armature for continuity.
Replace if out of specifications.
Checking the brushes
1. Measure the brush length. Replace the
brush assembly if out of specification.2. Check the brush holder for continuity.
Replace if out of specifications.
Checking the starter motor operation
1. Check the operation of the starter motor
after installing it to the power unit. Commutator undercut limit:
0.2 mm (0.01 in)
Armature continuity
Commutator segments b
 Continuity
Segment – 
Armature core c
 No continuity
Segment – 
Armature shaft d
 No continuity
Brush length limit a
: 12.0 mm (0.47 in)
Brush assembly continuity
Brush 1
 – Brush 2
 Continuity
Brush 1
 – Brush 3
 
Brush 2
 – Brush 3
 
Brush holder 4
 – Brush 
assembly holder 5
 No continuity
Starter motor 
						

							ELECElectrical systems
–+
8-2562Y3A11
Charging system8
1Lighting coil
2Rectifier Regulator
3Fuse
4BatteryB: Black
G: Green
R: Red
G/W : Green/white 
						

							62Y3A118-26
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Checking the lighting coil
1. Measure the lighting coil output peak
voltage. Replace the stator coil if below
specification.
 WARNING
When checking the peak voltage do not
touch any of the connections of the digital
tester leads.
NOTE:
Use the peak voltage adaptor with the digi-
tal circuit tester.
When measuring the peak voltage, set the
selector on the digital circuit tester to the
DC voltage mode
.
Checking the Rectifier Regulator
1. Measure the Rectifier Regulator output
peak voltage. If below specification, mea-
sure the lighting coil output peak voltage.
Replace the Rectifier Regulator if the out-
put peak voltage of the lighting coil is
above specification. 
 WARNING
When checking the peak voltage do not
touch any of the connections of the digital
tester leads.
NOTE:
Use the peak voltage adaptor with the digi-
tal circuit tester.
When measuring the peak voltage, set the
selector on the digital circuit tester to the
DC voltage mode
. Digital multimeter: YU-34899-A
Digital circuit tester: 90890-03174
Peak voltage adaptor:
YU-39991 / 90890-03172
Test harness (3 pins):
YB-06770 / 90890-06770
Lighting coil output peak voltage:
Green (G) – Green (G)
r/minUnloaded
Cranking 1,500 3,500
DC V 11.9 42 127
Lighting coil resistance (use as reference):
Green (G) – Green (G)
1.2–1.8 Ω
 at 20 °C (68 °F)
Digital multimeter: YU-34899-A
Digital circuit tester: 90890-03174
Peak voltage adaptor:
YU-39991 / 90890-03172
Test harness (4 pins):
YB-06771 / 90890-06771
Charging system 
						

							ELECElectrical systems
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8-2762Y3A11
NOTE:
After starting the engine, disconnect the out-
put lead (red lead) of the Rectifier Regulator
when measuring the output peak voltage.Rectifier Regulator output peak voltage:
Red (R) – Black (B)
r/minUnloaded
1,500 3,500
DC V 18.9 19.5 
						

							62Y3A118-28
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— MEMO — 
						

							Index
i-162Y3A11
A.
Acceleration pump .................................... 1-15
Adjusting the dash-pot 
(acceleration pump) ................................ 4-24
Adjusting the pilot screw ........................... 4-22
Adjusting the throttle link rod..................... 4-21
Adjusting the trim sensor .......................... 7-46
After test run ............................................. 1-36
Applicable models ....................................... 1-5
Assembling the carburetor ........................ 4-20
Assembling the cylinder body ................... 5-64
Assembling the drive shaft .............. 6-27
, 6-66
Assembling the forward gear .......... 6-27
, 6-65
Assembling the fuel pump......................... 4-10
Assembling the gear pump ....................... 7-66
Assembling the lower case ............. 6-25
, 6-63
Assembling the oil pan .............................. 7-39
Assembling the power trim and tilt motor .. 7-76
Assembling the propeller shaft 
assembly ....................................... 6-16
, 6-55
Assembling the propeller shaft 
housing ......................................... 6-16
, 6-55
Assembling the tiller handle ............ 7-15
, 7-23
Assembling the tilt cylinder ....................... 7-69
Assembling the trim cylinder ..................... 7-67
B.
Backlash (F50/F50A) ................................ 6-39
Backlash (T50/FT50B, FT50C) ................. 6-77
Bleeding the power trim and tilt (built-in)... 7-71
Bleeding the power trim and tilt 
(not installed) .......................................... 7-70
Bottom cowling.......................................... 7-25
Break-in..................................................... 1-36
C.
Carburetor ........................................1-10, 4-17
Carburetor unit .......................................... 4-11
CDI unit with microcomputer ....................... 1-7
Charging system ....................................... 8-25
Check the valves....................................... 7-65
Checking the anodes ................................ 3-19
Checking the armature.............................. 8-23
Checking the battery ....................... 1-33
, 3-20
Checking the bearings .................... 6-25
, 6-63
Checking the brushes ............................... 8-24
Checking the camshaft ............................. 5-45
Checking the carburetor............................ 4-19
Checking the CDI unit ............................... 8-15
Checking the charge coil........................... 8-15
Checking the compression pressure......... 5-25Checking the connecting rod big end side 
clearance ................................................ 5-59
Checking the connecting rod bolt ............. 5-59
Checking the connecting rod small end 
inside diameter ....................................... 5-59
Checking the cooling water passage ........ 3-13
Checking the crankshaft ........................... 5-59
Checking the crankshaft main journal oil 
clearance ................................................ 5-60
Checking the crankshaft pin oil 
clearance ................................................ 5-61
Checking the cylinder bore ....................... 5-56
Checking the cylinder head ...................... 5-46
Checking the diaphragm and valves ........ 4-10
Checking the drive shaft ..................6-25
, 6-63
Checking the electrical components ........... 8-4
Checking the engine idle speed ............... 3-15
Checking the engine oil .....................1-33
, 3-5
Checking the engine shut-off switch ......... 8-17
Checking the engine start switch .............. 8-17
Checking the engine start switch and engine 
stop switch/engine shut-off switch .......... 1-35
Checking the filters ................................... 7-65
Checking the fuel filter ................................ 3-5
Checking the fuel joint and fuel hoses 
(fuel joint-to-carburetor) ............................ 3-4
Checking the fuel pump .............................. 4-9
Checking the fuel system ......................... 1-33
Checking the fuse ............................7-79
, 8-20
Checking the gear oil ................................ 1-33
Checking the gear oil level ....................... 3-17
Checking the gear pump .......................... 7-66
Checking the gearshift and 
throttle operation..................................... 1-34
Checking the gearshift operation .............. 3-14
Checking the ignition coil .......................... 8-14
Checking the ignition spark gap ............... 8-13
Checking the ignition timing...................... 3-15
Checking the lighting coil .......................... 8-26
Checking the lower case .................6-25
, 6-63
Checking the lower unit (for air leakage) .. 3-19
Checking the neutral switch...................... 8-20
Checking the oil pressure ......................... 5-25
Checking the oil pressure switch .............. 8-18
Checking the oil pump .............................. 5-47
Checking the oil strainer and the 
relief valve .............................................. 7-39
Checking the outboard motor mounting 
position ................................................... 1-34
Checking the pilot water outlet ................. 1-35
Checking the pinion and 
forward gear ..................................6-25
, 6-63
Checking the piston clearance ................. 5-57