Checking The Piston Diameter; Checking The Cylinder Bore; Checking The Piston Ring - SELVA MARINE Kingfish 25 Service Manual

POWR
6. Remove the piston pin clips B and pis-
ton pin C, and then remove the connect-
ing rod c.
B
c
TIP:
Make sure to keep the parts in the order as
they were removed.
7. Remove the piston rings.

Checking the piston diameter

1. Measure the piston diameter a at the
specified measuring point b.
b
a
Piston diameter a:
64.950–64.965 mm (2.5571–2.5577 in)
Measuring point b:
5.0 mm (0.20 in) up from the bottom of
the piston skirt
Oversize piston diameter:
Oversize 1st:
65.200–65.215 mm (2.5669–2.5675 in)
Oversize 2nd:
65.450–65.465 mm (2.5768–2.5774 in)
7-57
Power unit
C
B

Checking the cylinder bore

1. Measure the cylinder bore (D
measuring points a, b, and c, and in
direction d (D
, D
1
to the crankshaft, and in direction e (D
D , D ), which is at a right angle to the
4 6
crankshaft.
a
b
D
2
c
D
4
D
6
a 10.0 mm (0.39 in)
b 48.0 mm (1.89 in)
c 85.0 mm (3.35 in)
Cylinder bore (D –D
1
65.000–65.015 mm (2.5591–2.5596 in)

Checking the piston ring

1. Measure the piston ring dimensions B
and T.
a
B
T
c
T
Piston ring dimensions:
Top ring a:
B: 1.170–1.190 mm (0.0461–0.0469 in)
T: 2.300–2.500 mm (0.0906–0.0984 in)
2nd ring b:
B: 1.470–1.490 mm (0.0579–0.0587 in)
T: 2.600–2.800 mm (0.1024–0.1102 in)
Oil ring c:
B: 2.360–2.480 mm (0.0929–0.0976 in)
T: 2.750 mm (0.1083 in) (reference
data)
–D ) at
1 6
, D ), which is parallel
3 5
D
1
d
D
3
e
D
5
):
6
b
B
T
B
,
2