Yanmar 3HM - Valve Cover; Breather Assembly

S INGLE-CYL INDER ENG INES
1. Never place any part of your body wher e a movin g or
falling engine may trap.
CUI or crush you.
2. If
you must push the engine during removal, use a
board or similar tool to keep your hands out of danger.
3. Make sure the hoist is designed to
lin engines and has
enough load capacity for your engine.
4. Make sure the hoist is securely attached to safe lifting
points on the engine.
5. The engine should not be difficult to lift with a proper
hoist. If
it is. stop lifting. lower the engine back onto its
mounts and make sure the engine has been completely
separated from the vessel.
Remcval/ tnstetlarton
While specific procedures cannot address all engine in-
stallations. r ef er to the following general instructions
when removing the engine.
1. Disconnect the negative battery cable.
2. Close the seacock and drain
the cooling system as de-
scribed in Chapter Four.
3. Disconnect the intake water hose from the seawater
cooling pump.
71
4. Close the fuel shutoff valve and disconnect the fuel
line and the fuel return line.
5. Disconnect the remote contro l cables.
6.
Disconnect the electrical wiring harness connectors.
7. Disconnect the electrical wires from the electric starter
motor and solenoid that will interfere with engine re-
moval.
8. Detach the exhaust system.
9. Detach the driveshaft from the transmission output 5
flange.
10. Remove the eng ine retaining bolts.
II . Remove the engi ne and transmiss ion.
12. Remove the transmission from the engine as de-
scribed in Chapter Ten.
13. Engine installation is the reverse
of removal, plus the
following:
a. Tighten the
eng ine mounting bolts securely.
b. Securely tighten the output flange-to-driveshaft
bolts.
e.
Bleed the fuel system at the fuel filter as described
under Fuel Filter in Chapter Three.
VALVE CO VER
Refer 10
F I ~ uTe 5.
To remove the valve cover, proceed as follows:
I. Make sure the decompression lever is in the OFF posi-
tion.
2. Unscrew the retaining nut (Figure 6).
3. Remove the valve cover.
4. Remove the gasket.
5. Clean the gaske t surfaces on the valve cover and cylin-
der head.
6. Reverse the removalsteps to installthe valve cover. Be
sure 10 in
stallthe breather pipe (19, Figure 5).
BREATH
ER ASS E ~ I BLY
A reed-type breather is located in the valve cover. Refer
to Chapter Three for a description of breather operation.
To service the reed portion
of the breather, remove the
breather
cover (Figure 7). The reed (Figure 8) should lie
flat. Replace the reed if it is split, cracked or otherwise
damaged .
Check the oil return hole (Figure 9) inside the breather
chamber in the valve cover.
If the hole is obstructed. re-
move the valve cover and clean out the hole .