ENGINE
Inspecting the Cylinder Block and Components
5-32
6LY3 Service Manual
© 2007 Yanmar Marine International
Inspecting the Valve Guide Projection
The valve guide should extend the specified
distance above the top of the cylinder head
(Figure 5-26)
.
Figure 5-26
Figure 5-26
1 – Exhaust Valve
2 – Intake Valve
Inspecting the Valve Stem Seals
The valve stem seals on the intake / exhaust valve
guides cannot be reused. Replace used seals with
new ones.
Lubricate the valve stems before installing the new
stem seals on the intake
(Figure 5-26, (2))
and
exhaust valves
(Figure 5-26, (1))
. Exhaust stem
seals are marked yellow. Intake stem seals are not
marked.
Installing the Valve Stem Seal
1. Place a tool stop against the cylinder head; over
the valve stem
(Figure 5-27, (1))
.
2. Place the valve stem seal
(Figure 5-27, (4))
on
the guide pin
(Figure 5-27, (2))
.
3. Place the guide pin and seal on the valve stem.
Check that the spring
(Figure 5-27, (3))
is still
in position on the seal.
4. Use the valve stem seal installer tool to install
the seal. Tap the seal in position using a tool
stop
(Figure 5-27, (6))
to prevent damage to
the valve stem seal.
5. Remove the tools and verify that the seal is
against the top of the valve guide
(Figure 5-27, (5))
.
Figure 5-27
Figure 5-27
1 – Valve Stem Seal Installer
2 – Guide Pin
3 – Seal Spring
4 – Valve Stem Seal
5 – Seal Against Top of Valve Guide
6 – Tool Stop
Checking the Valve Springs
1. Check the valve spring for scratches or
corrosion.
Figure 5-28
Figure 5-28
2. Measure the free length of the spring.
0005607
9.5
11
.5
7
+0.5
0
9
+0.5
0
(1)
(2)
000560
8
(6)
(5)
(4)
(
3
)
(2)
(1)
0005609
