Yamaha F50 Service Manual

							62Y3A115-64
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6. If the oil clearance is below specification,
check the connecting rod bearing color
and clean the contact surface of the con-
necting rod and the connecting rod bear-
ing, and then check the crank pin oil
clearance again.
7. If the oil clearance is over specification,
install an over-sized connecting rod bear-
ing, and then check the crank pin oil
clearance again.
Assembling the cylinder body
1. Assemble the piston 1
, connecting rod
2
, piston pin 3
, and piston pin clips 4
.
NOTE:
Face the embossed “Y” mark a
 on the
connecting rod in the same direction as the
“UP” mark b
 on the piston.
Always use new piston pin clips, and do not
allow the piston pin clip end to align with the
piston pin slot c
.
2. Install the oil ring 5
, second ring 6
, and
top ring 7
 to the piston with the “T” mark
d
 on the piston rings facing upward.3. Offset the piston ring end gaps as
shown.
CAUTION:
Do not scratch the piston or break the pis-
ton rings.
NOTE:
After installing the piston rings, check that
they move smoothly.
4. Install the upper half of the bearing into
the connecting rod 2
 and the lower half
into the connecting rod cap 8
.
CAUTION:
Install the bearings in their original posi-
tion.
NOTE:
Insert the projection e
 of the bearing into the
slot on the cap and connecting rod.
Cylinder body 
						

							POWRPower unit
5-6562Y3A11
5. Install the piston with the “UP” mark on
the piston crown facing towards the fly-
wheel.
ÈFor USA and Canada
ÉFor worldwide
NOTE:
Apply engine oil to side of the piston assem-
bly.
6. Install half of the bearings 9
 into the cyl-
inder body 0
.
NOTE:
Insert the projection 
f of the bearing into the
notch in the cylinder body.7. Set the crankshaft A
, and oil seals B
and C
 into the cylinder body as shown.
Apply engine oil to the inner oil seal, jour-
nal bearings, and connecting rod bear-
ing.
8. Install the connecting rod cap 8
 to the
connecting rod, and then tighten the con-
necting rod bolts D
 to the specified
torques in two stages. Apply engine oil to
the connecting rod cap and connecting
rod bolt.
Piston ring compressor: YU-33294
Piston slider: 90890-06529
S62Y5A81
0
9
S62Y5A80
8 D
E
E 
						

							62Y3A115-66
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NOTE:
Align the alignment marks g
 on the connect-
ing rod cap and connecting rod.
9. Install half of the bearings 9
 into the
crankcase, then dowel pins E
.
10. Apply Gasket Maker
® to the mating sur-
face of the crankcase.
NOTE:
Insert the projection h
 of the bearing into
the notch in the crankcase.
Do not get any Gasket Maker on the journal
bearings.
11. Install the crankcase bolts, and then
tighten them to the specified torques in
two stages and in the sequence shown.
CAUTION:
The oil seals must be installed before
tightening the crankcase bolts.
NOTE:
Apply engine oil to the crankcase bolt (M8)
before installation. Connecting rod bolt:
1st: 6 N·m (0.6 kgf·m, 4.3 ft·lb)
2nd: 17 N·m (1.7 kgf·m, 12 ft·lb)
S62Y5A90
GM
E
E
9
E
Crankcase bolt (M8):
1st: 15 N·m (1.5 kgf·m, 11 ft·lb)
2nd: 30 N·m (3.0 kgf·m, 22 ft·lb)
Crankcase bolt (M6):
1st: 6 N·m (0.6 kgf·m, 4.3 ft·lb)
2nd: 12 N·m (1.2 kgf·m, 8.7 ft·lb)
Cylinder body 
						

							POWRPower unit
5-6762Y3A11
12. Install the new gasket and exhaust cover,
and then tighten the bolts to the specified
torques in two stages and in the
sequence shown.
Installing the power unit
1. Install the dowel pins 1
 and gasket 2
.
2. Install the power unit 3
 by installing the
bolts 4
, then tightening them to the
specified torque.3. Install the apron 5
. Exhaust cover bolt:
1st: 6 N·m (0.6 kgf·m, 4.3 ft·lb)
2nd: 12 N·m (1.2 kgf·m, 8.7 ft·lb)
Mounting bolt 4
:
21 N·m (2.1 kgf·m, 15 ft·lb) 
						

							62Y3A115-68
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4. Install the shift rod bolts 6
, shift rod 7
and power trim and tilt relay 8
.
5. Connect the flushing hose (models with
flushing device), pilot water hose 9
,
trailer switch coupler 0
 (EHT, ET), warn-
ing indicator coupler A
 (EHD, EHT),
ground lead B
 (EHT, ET), PTT motor
leads C
 (EHT, ET), PTT relay leads D
(EHT, ET), 10-pin coupler E
, and battery
leads F
.6. Connect the throttle link rod G
 and fuel
hose H
.
7. Connect the shift cable/shift rod I
 and
throttle cable J
, and then adjust their
lengths. For adjustment procedures, see
Chapter 3, “Checking the throttle cable
operation,” and “Checking the gearshift
operation.”
Cylinder body 
						

							POWRPower unit
5-6962Y3A11
8. Install the Woodruff key.
9. Install the flywheel magnet and flywheel
magnet cover.
ÈFor USA and Canada
ÉFor worldwide
CAUTION:
Apply force in the direction of the arrows
shown, to prevent the flywheel holder
from slipping off easily.
NOTE:
Apply engine oil to the flywheel magnet nut
before installation.
Flywheel magnet holder: YB-06139
Flywheel holder: 90890-06522
Flywheel magnet nut:
160 N·m (16 kgf·m, 116 ft·lb) 
						

							62Y3A115-70
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— MEMO — 
						

							LOWR
62Y3A11
Lower unit
Special service tools ..................................................................................... 6-1
Lower unit (F50/F50A).................................................................................... 6-7
Removing the lower unit ............................................................................ 6-9
Water pump and propeller shaft housing (F50/F50A)............................... 6-11
Removing the water pump and propeller shaft housing assembly .......... 6-13
Disassembling the propeller shaft housing .............................................. 6-13
Disassembling the propeller shaft assembly ........................................... 6-14
Checking the water pump ........................................................................ 6-14
Checking the propeller shaft housing ...................................................... 6-15
Checking the propeller shaft .................................................................... 6-15
Assembling the propeller shaft assembly ................................................ 6-16
Assembling the propeller shaft housing................................................... 6-16
Installing the propeller shaft housing ....................................................... 6-18
Installing the water pump......................................................................... 6-18
Drive shaft and lower case (F50/F50A) ...................................................... 6-21
Removing the drive shaft ......................................................................... 6-23
Disassembling the drive shaft assembly ................................................. 6-23
Disassembling the forward gear .............................................................. 6-23
Disassembling the lower case ................................................................. 6-24
Checking the pinion and forward gear ..................................................... 6-25
Checking the bearings ............................................................................. 6-25
Checking the drive shaft .......................................................................... 6-25
Checking the shift rod and shift cam ....................................................... 6-25
Checking the lower case ......................................................................... 6-25
Assembling the lower case ...................................................................... 6-25
Assembling the forward gear ................................................................... 6-27
Assembling the drive shaft ...................................................................... 6-27
Installing the drive shaft ........................................................................... 6-28
Installing the lower unit ............................................................................ 6-28
Shimming (F50) (for USA and Canada) ...................................................... 6-31
Shimming................................................................................................. 6-32
Selecting the pinion shims ....................................................................... 6-32
Selecting the forward gear shims ............................................................ 6-33
Selecting the reverse gear shims ............................................................ 6-34
Shimming (F50A) (for worldwide) ............................................................... 6-35
Shimming................................................................................................. 6-36
Selecting the pinion shims ....................................................................... 6-36
Selecting the forward gear shims ............................................................ 6-37
Selecting the reverse gear shims ............................................................ 6-38 
						

							62Y3A11
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Backlash (F50/F50A) .................................................................................... 6-39
Measuring the forward and reverse gear backlash ................................. 6-39
Lower unit (T50/FT50B, FT50C) .................................................................. 6-41
Removing the lower unit .......................................................................... 6-43
Water pump and shift rod (T50/FT50B, FT50C) ......................................... 6-45
Removing the water pump and shift rod .................................................. 6-47
Checking the water pump and shift rod ................................................... 6-47
Installing the water pump and shift rod .................................................... 6-48
Propeller shaft housing (T50/FT50B, FT50C) ............................................ 6-51
Removing the propeller shaft housing assembly ..................................... 6-53
Disassembling the propeller shaft housing .............................................. 6-53
Disassembling the propeller shaft assembly ........................................... 6-54
Checking the propeller shaft housing ...................................................... 6-54
Checking the propeller shaft .................................................................... 6-55
Assembling the propeller shaft assembly ................................................ 6-55
Assembling the propeller shaft housing................................................... 6-55
Installing the propeller shaft housing ....................................................... 6-57
Drive shaft and lower case (T50/FT50B, FT50C) ....................................... 6-59
Removing the drive shaft ......................................................................... 6-61
Disassembling the drive shaft.................................................................. 6-61
Disassembling the forward gear .............................................................. 6-61
Disassembling the lower case ................................................................. 6-62
Checking the pinion and forward gear ..................................................... 6-63
Checking the bearings ............................................................................. 6-63
Checking the drive shaft .......................................................................... 6-63
Checking the lower case ......................................................................... 6-63
Assembling the lower case ...................................................................... 6-63
Assembling the forward gear ................................................................... 6-65
Assembling the drive shaft ...................................................................... 6-66
Installing the drive shaft ........................................................................... 6-66
Installing the lower unit ............................................................................ 6-66
Shimming (T50) (for USA and Canada) ...................................................... 6-69
Shimming................................................................................................. 6-70
Selecting the pinion shims ....................................................................... 6-70
Selecting the forward gear shims ............................................................ 6-71
Shimming (FT50B, FT50C) (for worldwide)................................................ 6-73
Shimming................................................................................................. 6-74
Selecting the pinion shims ....................................................................... 6-74
Selecting the forward gear shims ............................................................ 6-75
Backlash (T50/FT50B, FT50C) ..................................................................... 6-77
Measuring the forward and reverse gear backlash ................................. 6-77 
						

							LOWRLower unit
6-162Y3A11
Special service tools6
Bearing housing puller
YB-06207, YB-06234
Universal puller
YB-06117
Slide hammer and adapters
YB-06096
Bearing housing needle bearing remover
YB-06112, YB-06153
Driver handle
YB-06071Bearing housing needle bearing installer
YB-06111
Oil seal installer
YB-06168
Forward/reverse gear bearing installer
YB-06270-A
Bearing cup installer
YB-06167
Drive shaft holder
YB-06049
For USA and Canada