Yamaha F4B Service Manual

1-7
SPEC
Specification
Cylinder head assembly
(*1) The figures are for reference only.
Item Unit
Model
F4BMH F5AMH F6CMH
Valve
Clearance
Intake and exhaust mm (in) 0.08–0.12 (0.003–0.005)
Margin thickness
Intake mm (in) 0.800–1.200 (0.0315–0.0472)
Exhaust mm (in) 1.100–1.500 (0.0433–0.0591)
Runout (*1)
Intake mm (in) 0.050 (0.0020)
Exhaust mm (in) 0.030 (0.0012)
Seat contact width
Intake and exhaust mm (in) 0.6–0.8 (0.02–0.03)
Cylinder head
Warpage limit 0.10 (0.0039)
Push rod
Runout
Intake and exhaust mm (in)
0.5 (0.02)
Valve spring
Free length mm (in) 27.6 (1.09)
Tilt limit mm (in) 1.0 (0.04)
Valve stem
Diameter
Intake mm (in) 5.475–5.490 (0.2156–0.2161)
Exhaust mm (in) 5.460–5.475 (0.2150–0.2156)
Runout (*1)
Intake mm (in) 0.050 (0.0020)
Exhaust mm (in) 0.030 (0.0012)
Valve guide
Inside diameter
Intake and exhaust mm (in) 5.500–5.512 (0.2165–0.2170)
Clearance
Intake mm (in) 0.010–0.037 (0.0004–0.0015)
Exhaust mm (in) 0.025–0.052 (0.0010–0.0020)
Installation height mm (in) 8.2–9.1 (0.32–0.36)
Cam shaft
Cam lobe height
Intake mm (in) 32.037–32.137 (1.2613–1.2652)
Exhaust mm (in) 32.038–32.138 (1.2613–1.2653)
Cam lobe width
Intake and exhaust mm (in) 26.950–27.050 (1.0610–1.0650)
Fuel pump cam diameter (*1) mm (in) 19.600 (0.7717)
Journal diameter mm (in) 14.965–14.990 (0.5892–0.5902)
Runout mm (in) 0.030 (0.0012)

Yamaha F4B Specifications

General

Brand	Yamaha
Model	F4B
Category	Outboard Motor
Language	English