Yanmar 1GM10 Shop Manual Download

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MULTICYLINDER ENGINES

105

Exhaust

manifold

Cover

6.  Clean  any  gasket residue from  the  exhaust  manifold
and cylinder head.
7.  Remove the exhaust  manifold cover retaining screws
and remove the manifold cover (Figure 7).
8.  Inspect  the exhaust  manifold  and  cover for
carbon buildup and corrosion.
9.  Reinstall the exhaust manifold and cover by reversing
the removal  procedure.  Tighten  the retaining  nuts to the

torque specified in Table 2.

3HMF and

models with freshwater (closed)

cooling system

Refer to Figure 6.

1.  Refer to Chapter Four and drain the cooling system.
2.  Detach the exhaust hose from the exhaust elbow.
3.  Remove the water hose from the exhaust manifold and
thermostat housing.

4. Remove the water hose from the exhaust manifold and
freshwater pump.

5. Disconnect the water hoses from the manifold end
caps.

6. Disconnect the water hose to the overflow tank.

Remove the exhaust manifold from the cylinder head.

8. Clean any gasket residue from the exhaust manifold
and cylinder head.

9. Check the exhaust manifold for

carbon

buildup and corrosion.
10. If necessary, refer to Chapter Eight to service the heat

inside the exhaust manifold.

11. Reverse the removal procedure to install the exhaust
manifold. Tighten the manifold bolts to the torque speci-
fied in Table 2. Fill the freshwater section of the closed

cooling

with coolant as described in Chapter

Three.

CYLINDER HEAD

Removal

In some instances, the cylinder head may be removed

for service without removing the engine. If engine re-

moval is necessary, refer to the engine removal procedure.
Refer to Figure 8 for an exploded view of the cylinder
head assembly.

To remove the cylinder head, proceed as follows:

1. Disconnect the negative battery cable from the nega-
tive battery terminal.
2. If not previously performed, drain the cooling system

as described in Chapter Four.

Remove the alternator as described in Chapter Eight.

4. Remove the exhaust manifold as previously described.
5 .

Disconnect the wire lead from the water temperature

sender (Figure 9).
6A. Engines with standard cooling-Disconnect the
lower water hose (Figure 9) from the thermostat housing.
6B. Engines with freshwater (closed) cooling sys-
tem-Remove the freshwater pump as described in Chap-
ter Eight.
7.

Remove the air cleaner and the air cleaner base.

8. Remove the fuel injector and precombustion chamber
as described in Chapter Seven.

9. Remove the valve cover as previously described.

10. Remove the nuts that retain the rocker arm stands
(Figure

then remove the rocker shaft assembly.

11.  Remove the push rods and mark them so they can be
reinstalled in their original positions.
12.  Detach the oil line fitting from the cylinder head.
13.  Unscrew  the  smaller  cylinder  head  retaining  bolts
first, then unscrew the larger bolts and nuts in a crossing
pattern.
14.  Remove the cylinder head and head gasket.

Inspection

Refer to the Anticorrosion Maintenance section in

Chapter Three. Remove and inspect the sacrificial anode.
Install the anode in the cylinder head after completing cyl-

inder head service.
2. If service to the valves or rocker assembly is required,
refer to the

and Rocker Assembly sections.

3. Check the cylinder head for signs of oil or water leak-
age before cleaning. Look for corrosion or foreign mate-

rial in the oil and water passages.