Crank Cylinder Assembly; Cylinder Head And Exhaust Cover - Yamaha 20C Service Manual

POWR
ASSEMBLY AND ADJUSTMENT
G74000-0*

CRANK CYLINDER ASSEMBLY

1) Lubricate the piston-rings and pistons with 2-
stroke outboard-motor oil, and install then
crank assembly into the cylinder block.
2) Lift the crank assembly a little so as to be able
to install a washer on the lower crankcase, and
align each locating-clip of the bearings and
labyrinth-seals with each cut on the cylinder-
block, then fit the crank assembly in place.
3) Film-coat the cylinder-block mating surface with
GasketMaker or equivalent.
4) Install the dowel-pins.
5) Match the cylinder-block and tighten the bolts in
sequence and in two steps of torque.
Crank case:
1st step:
15 Nm (1.5 m·kg, 11 ft·lb)
2nd step:
28 Nm (2.8 m·kg, 20 ft·lb)
6) Check that the crankshaft turns smoothly.
G75000-0*

CYLINDER HEAD AND EXHAUST COVER

1) Install the gaskets, cylinder-head cover and
exhaust cover.
2) Tighten the bolts in two sequences and in two
steps of torque.
Cylinder head:
1st :15 Nm (1.5 m·kg, 11 ft·lb)
2nd :28 Nm (2.8 m·kg, 20 ft·lb)
Exhaust cover:
1st :4 Nm (0.4 m·kg, 2.9 ft·lb)
2nd :8 Nm (0.8 m·kg, 5.8 ft·lb)
3) Install the thermostat, gasket and cover.
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