ENGINE
5-34
6LPA Service Manual
Cylinder Head
© 2007 Yanmar Marine International
4. Determine the position where the piston head
(Figure 5-62, (1)) is at the upper-most position
(TDC) by slowly turning the crankshaft
clockwise and counter-clockwise
(Figure 5-62, (4)).
Figure 5-62
Figure 5-62
1 – Piston Head
2 – Piston Protrusion (P)
3 – Cylinder Block Top Surface
4 – Turning Crankshaft
5. Measure each cylinder at two points for a total
of 12 points (Figure 5-63, (1)).
6. Record each measurement and determine the
average of all.
• Piston protrusion (P) (Figure 5-62, (2)):
0.175 to 0.425 mm (0.0068 to 0.0167 in.)
If the measured value is not within the specified
range, remove the piston and connecting rod
assembly, and then reassemble and measure
again. See Cylinder Block Disassembly on
page 5-42.
Figure 5-63
Figure 5-63
7. There are three thicknesses of service gaskets,
(Mark No. 1, 3 and 5) (Figure 5-64).
Figure 5-64
Figure 5-64
1 – Front
2 – Mark No. “1”
3 – Mark No. “3”
4 – Mark No. “5”
(2)
(
3
)
(1)
(4)
0005090
New Head Gasket Thickness
Mark No. 1
0.85 to 0.95 mm (0.033 to 0.037 in.)
Mark No. 3
0.95 to 1.05 mm (0.037 to 0.041 in.)
Mark No. 5
1.05 to 1.15 mm (0.041 to 0.045 in.)
(1)
(1)
(1)
(1)
(1)
(1)
0005091
(1)
(2)
(
3
)
(4)
0005092
