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Yanmar marine engine 6LPA-STP2, 6LPA-STZP2. Manual - part 17

PERIODIC MAINTENANCE

6LPA Series Operation Manual

12/05

Perform the following maintenance every
1000 hours or 4 years of operation,
whichever comes first.

• Checking the Fuel Injection Timing

• Checking the Fuel Injector Pressure

and Nozzle Spray Pattern

• Replacing the Seawater Pump Impeller

• Adjusting Intake / Exhaust Valve

Clearance

• Lapping the Intake and Exhaust Valves

Checking the Fuel Injection Timing

See your authorized Yanmar Marine dealer
or distributor.

Checking the Fuel Injector Pressure
and Nozzle Spray Pattern

See your authorized Yanmar Marine dealer
or distributor.

Checking or Replacing Seawater
Pump Impeller

Figure 17

Figure 17

1 – Impeller
2 – O-Ring
3 – Cover
4 – Cover Bolts

1. Close the seacock.
2. Drain the seawater cooling system. See

Drain Seawater Cooling System on
page 74

3. Loosen the cover bolts and remove the

cover and O-ring.

4. Inspect the inside of the seawater

pump with a flashlight. If any of the
following are found, disassembly and
maintenance are required:
• Impeller blades are cracked or nicked.

Edges or surfaces of the blades are
marred or scratched.

• Wear plate is damaged.

5. If no damage is found when inspecting

the inside of the pump, install the O-ring
and cover.

6. If a large amount of water leaks

continuously from the water drain line
below the seawater pump during
operation, replace the mechanical seal.
See your authorized Yanmar Marine
dealer or distributor.

7. When replacement is required, see

your authorized Yanmar Marine dealer
or distributor.

NOTICE

Replace the seawater pump impeller every
1000 hours even if no damage is apparent.

Adjusting Intake / Exhaust
Valve Clearance

See your authorized Yanmar Marine dealer
or distributor.

Lapping the Intake and Exhaust
Valve

See your authorized Yanmar Marine dealer
or distributor.

Every 1000 Hours of Operation

(4)

(3)

(1)

(2)

0004914

PERIODIC MAINTENANCE

6LPA Series Operation Manual

Perform the following maintenance
procedures every 1250 hours of operation
or 5 years, whichever comes first.

• Cleaning the Cooling Water System
• Cleaning and Checking the Seawater

Passage

• Cleaning and Checking the Fresh

Water Cooling Water Passage

• Adjusting the Tension of the

Alternator V-Belt

• Replacing the Timing Belt
• Washing Engine Oil Cooler
• Replacing the Front Rubber Damper

Cleaning the Cooling Water System

See your authorized Yanmar Marine dealer
or distributor.

Cleaning and Checking the
Seawater Passage

See your authorized Yanmar Marine dealer
or distributor.

Cleaning and Checking the Fresh
Water Cooling Water Passage

See your authorized Yanmar Marine dealer
or distributor.

Adjusting the Tension of the
Alternator V-Belt

See Checking and Adjusting the Alternator
V-Belt Tension on page 66

Replacing the Timing Belt

See your authorized Yanmar Marine dealer
or distributor.

Washing the Engine Cooler

See your authorized Yanmar Marine dealer
or distributor.

Replacing the Front Rubber Damper

See your authorized Yanmar Marine dealer
or distributor.

Every 1250 Hours of Operation

6LPA Series Operation Manual

TROUBLESHOOTING

SAFETY PRECAUTIONS

Before performing any troubleshooting
procedures within this section, review the
Safety

section on page

If a problem occurs, stop the engine
immediately. Refer to the Symptom column
in the Troubleshooting Chart to identify the
problem.

TROUBLESHOOTING
AFTER STARTING

Just after the engine has started, check
the following items at a low engine speed:

Is sufficient water being discharged
from the seawater outlet pipe?

If the discharge is low, stop the engine
immediately. Identify the cause and repair.

Is the smoke color normal?

The continuous emission of black exhaust
smoke indicates engine overloading. This
shortens the engines life and should be
avoided.

Are there abnormal vibrations or noise?

Depending on the hull structure, engine
and hull resonance may suddenly increase
at certain engine speed ranges, causing
heavy vibrations. Avoid operation in this
speed range. If any abnormal sounds are
heard, stop the engine and inspect for
cause.

Alarm sounds during operation.

If the alarm sounds during operation, lower
the engine speed immediately, check the
alarm lamps and stop the engine for
repairs.

TROUBLESHOOTING

6LPA Series Operation Manual

Is there water, oil or fuel leakage? Are
there any loose bolts or connections?

Check the engine room daily for any leaks
or loose connections.

Is there sufficient fuel in the fuel tank?

Refill fuel in advance to avoid running out
of fuel. If the tank runs out of fuel, bleed
the fuel system. See Bleeding the Fuel
System on page 29

When operating the engine at low speed
for long periods of time, race the engine
once every 2 hours. Racing the engine
with the clutch in NEUTRAL, accelerate
from the low-speed position to the
high-speed position and repeat this
process about five times. This is done to
clean out carbon from the cylinders and
the fuel injection valves.

NOTICE

Neglecting to race the engine will result in
poor smoke color and reduce engine
performance.

Periodically operate the engine near
maximum speed while underway. This will
generate higher exhaust temperatures,
which will help clean out hard carbon
deposits, maintain engine performance
and prolong the life of the engine.

TROUBLESHOOTING
INFORMATION

If the engine does not operate properly,
refer to the Troubleshooting Chart on page
71

or see your authorized Yanmar Marine

dealer or distributor.

Supply the authorized Yanmar Marine
dealer or distributor with the following
information:

• Model name and serial number of your

engine

• Boat model, hull material, size (tons)

• Use, type of boating, number of hours

run

• Total number of operation hours (refer to

hourmeter), age of boat

• The operating conditions when the

problem occurs:

• Engine speed (min

-1

)

• Color of smoke
• Type of diesel fuel
• Type of engine oil
• Any abnormal noises or vibration
• Operating environment such as high

altitude or extreme ambient
temperatures, etc.

• Engine maintenance history and

previous problems

• Other factors that contribute to the

problem

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