Volvo Penta TAMD31P, AD31L, AD31P, KAD32P, TAMD41H Workshop Manual

Workshop Manual

Engine unit

MD6A, MD7A

AB Volvo Penta
Customer Support
Dept. 42200
SE-405 08 Gothenburg
Sweden

A

2 (0)

Workshop Manual

Marine diesel engines

MD6A, MD7A

Contents

Safety Precautions 2
General information 5
Repair methods 6
Presentation

MD6A 8
MD7A 9

Repair instructions 10
Electrical system 30
Special Tools 34
Technical Data 35

1

Safety Precautions

Introduction

This workshop manual contains technical data,
descriptions and repair instructions for Volvo Penta
products or product versions contained in the contents
list. Ensure that the correct workshop literature is being
used.

Read the safety information and the Workshop
Manual “General Information” and “Repair
Instructions” carefully before starting work.

Important

In this book and on the engine you will find the
following special warning symbols.

WARNING! If these instructions are not
followed there is a danger of personal injury,
extensive damage to the product or serious
mechanical malfunction.

IMPORTANT! Used to draw your attention to
something that can cause damage, product
malfunction or damage to property.

NOTE! Used to draw your attention to important
information that will facilitate work or operations.

Below is a summary of the risks and safety precautions
you should always observe or carry out when operating
or servicing the engine.

Immobilize the engine by turning off the power
supply to the engine at the main switch(es) and
lock it (them) in the OFF position before
starting work. Set up a warning notice at the
engine control point or helm.

Generally, all servicing should be carried out
with the engine switched off . Som e work
(carrying out certain adjustments for example)
requires the engine to be running. Approaching
a running engine is dangerous. Loose clothing
or long hair can fasten in rotating parts and
cause serious personal injury.
If working in proximity to a running engine,
careless movements or a dropped tool can
result in personal injury. Avoid burns. Take
precautions to avoid hot surfaces (exhausts,
turbochargers, charge air pipes and starter
elements, etc.) and liquids in supply lines and
hoses when the engine is running or has been
turned off immediately prior to starting work on
it. Reinstall all protective parts removed during
service operations before starting the engine.

Check that the warning information decals on
the product are always clearly visible.
Replace decals that have been damaged or
painted over.

Engine with turbocharger: Never start the en­gine without installing the air cleaner (ACL).
The rotating compressor in the Turbo can
cause serious personal injury. Foreign
objects entering the intake ducts can also
cause mechanical damage.

Never use start spray or similar to start the
engine. The starter element may cause an
explosion in the inlet manifold. Danger of
personal injury.

Avoid opening the filler cap for engine
coolant system (freshwater cooled engines)
when the engine is still hot. Steam or hot
coolant can spray out. Open the coolant filler
cap carefully and slowly to release pressure
before removing the cap completely. Take
great care if a cock, plug or engine coolant
line must be removed from a hot engine. It is
difficult to anticipate in which direction steam
or hot coolant can spray out.

Hot oil can cause burns. Avoid skin contact
with hot oil. Ensure that the lubrication
system is not under pressure before
commencing work on it. Never start or
operate the engine with the oil filler cap
removed, otherwise oil could be ejected.

Stop the engine and close the sea cock
before carrying out operations on the engine
cooling system.

Only start the engine in a well-ventilated
area. If operating the engine in an enclosed
space, ensure that exhaust gases and
crankcase ventilation emissions are
ventilated out of the working area.

2

A

lways use protective goggles where there is a
danger of pieces of metal, sparks from
grinding, acid or other chemicals being thrown
into your eyes. Your eyes are very sensitive,
injury can lead to loss of sight!

Avoid skin contact with oil. Long-t erm or
repeated contact with oil can remove the
natural oils from your skin. The result can be
irritation, dry skin, eczema and other skin
problems. Used oil is more dangerous to health
than new oil. Use protective gloves and avoid
using oil-soaked clothes and rags. Wash
regularly, especially before meals. Use the
correct barrier cream to prevent dry skin and to
make cleaning your skin easier.

Most chemicals used in products (engine and
transmission oils, glycol, petrol and diesel oil)
and workshop chemicals (solvents and pa ints)
are hazardous to health Read the instructions
on the product packaging carefully! Always fol­low safety instructions (using breathing appara­tus, protective goggles and gloves for exam­ple). Ensure that other personnel are not
unwittingly exposed to hazardous subst anc es
(by breathing them in for example). Ensure that
ventilation is good. Handle us ed and exces s
chemicals according to instructions.

Be extremely careful when tracing leaks in the
fuel system and testing fuel injection nozzles.
Use protective goggles! The jet ejected from a
fuel injection nozzle is under very high pres­sure, it can penetrate body tissue and cause
serious injury There is a danger of blood
poisoning.

All fuels and many chemicals are inflammable.
Ensure that a naked flame or sparks cannot ig­nite fuel or chemicals. Combined with air in cer­tain ratios, petrol, some solvents and hydrogen
from batteries are easily inflammable and
explosive. Smoking is prohibited! Ensure that
ventilation is good and that the neces s ary
safety precautions have been taken before
carrying out welding or grindin g work . Alwa ys
have a fire extinguisher to hand in the
workplace.

Store oil and fuel-soaked rags and fuel and
oil filters safely. In certain conditions oil­soaked rags can spontaneously ignite. Used
fuel and oil filters are environmentally
dangerous waste and must be deposited at
an approved site for destruction together with
used lubricating oil, contaminated fuel, paint
remnants, solvent, degreasing agents and
waste from washing parts.

Never allow a naked flame or electric sparks
near the batteries. Never smoke in proximity
to the batteries. The batteries give off
hydrogen gas during charging whic h when
mixed with air can form an explosive gas ­oxyhydrogen. This gas is easily ignited and
highly volatile. Incorrect connection of the
battery can cause a spark which is sufficient
to cause an explosion with resulting damage.
Do not disturb battery connections when
starting the engine (spark risk) and do not
lean over batteries.

Never mix up the positive and negative
battery terminals when installing. Incorrect
installation can result in serious damage to
electrical equipment. Refer to wiring
diagrams.

Always use protective goggles when
charging and handling batteries. The battery
electrolyte contains extremely corrosive
sulfuric acid. If this comes into contact with
the skin, wash immediatel y with soap and
plenty of water. If battery acid comes into
contact with the eyes, immediately flush with
copious amounts of water and obtain
medical assistance.

Turn off the engine and turn off power at
main switch(es) before carrying out work on
the electrical system.

Clutch adjustments must be carried out wit h
the engine turned off.

3

Use the lifting eyes mounted on the engine/re­verse gear when lifting the driv e unit.
Always check that lifting equipment is in good
condition and has sufficient load capacity to lift
the engine (engine weight including reverse
gear and any extra equipment installed).
To ensure safe handling and to avoid
damaging engine components on top of the
engine, use a lifting beam to raise the engine.
All chains and cables should run parallel to
each other and as perpendicular as possible in
relation to the top of the engine.
If extra equipment is installed on the engine al­tering its center of gravity, a special lifting de­vice is required to achieve the correct balance
for safe handling.
Never carry out work on an engine suspended
on a hoist.

Never remove heavy components alone, even
where secure lifting equipment such as
secured blocks are being used. Even where
lifting equipment is being used it is best to carry
out the work with two people; one to operate
the lifting equipment and the other to ensure
that components are not trapped and damaged
when being lifted.

When working on-board ensure that there is
sufficient space to remove components
without danger of injury or damage.

Components in the electrical system, ignition
system (gasoline engines) and fuel system
on Volvo Penta products are designed and
constructed to minimize the risk of fire and
explosion. The engine must not be run in
areas where there are explosive materials.

Always use fuels recommended by Volvo
Penta. Refer to the Instruction Book. The use
of lower quality fuels can damage the
engine. On a diesel engine poor quality fuel
can cause the control rod to seize and the
engine to over-rev with the resulting risk of
damage to the engine and personal injury.
Poor fuel quality can also lead to higher
maintenance costs.

4

General information

About the workshop manual

This workshop manual contains technical specifica­tion, descriptions and instructions for repairing the
standard versions of the following engines
TAMD31M, TAMD31L, TAMD31P, AD31L, AD31P,
KAD32P, TAMD41H, TAMD41M, TAMD41P, AD41P,
TAMD42WJ, KAMD42A, KAMD42B, KAMD42P,
KAD42A, KAD42B, KAD42P, KAMD43P, KAD43P,
KAMD44P, KAD44P. The work s hop manual dis p lays
the operations carried out on any of the engines
above. As a result the illustrations and pic t ur es in the
manual that show certain parts on the engines, do
not in some cases apply to all the engines listed
above. However the repair and ser vic e opera t ions
described are the same in all essential details.
Where they are not the same this is stated in the
manual and where the difference is considerable the
operations are described separately. Engine
designations and numbers are given on the number
plate (See Workshop manual Group 21 Engine page

15). The engine designation and number should be
given in all correspondence about the engine.

This Workshop Manual has been developed primarily
for Volvo Penta service workshops and qualified per­sonnel. Persons using this book are assumed to
have a grounding in marine drive systems and be
able to carry out related mechanical and electrical
work.

Volvo Penta is continuously developing their prod­ucts. We therefore reserve the right to make chang­es. All the information contained in this book is based
on product data available at the time of going to print.
Any essential changes or modifications introduced
into production or updated or revised service
methods introduced after the date of publication will
be provided in the form of Service Bulletins.

Replacement parts

Replacement parts for electrical and fuel systems are
subject to statutory requirements (US Coast Guard
Safety Regulations for example). Volvo Penta Genu­ine parts meet these requirements. Any type of dam­age which results from the use of non-original Volvo
Penta replacement parts for the product will not be
covered under any warranty provided by Volvo
Penta.

Certified engines

The manufacturer guarantees that certified new and
currently operational engines meet national and re­gional environmental regulations (in Lake Constance
for example). The product must be the same as the
example approved for certification purposes. So that
Volvo Penta, as a manufacturer, can guarantee that
currently operational engines meet environmental
regulations, the following service and replacement
part requirements must be observed:

• The Service Intervals and maintenance operations
recommended by Volvo Penta must be observed.

• Only Volvo Penta genuine replacement parts, in­tended for the certificated engine, may be used.

• The servicing of ignition, timing and fuel injection
systems (gasoline) or injector pumps, pump set­tings and injectors (diesel) must always be carried
out be an authorized Volvo Penta workshop.

• The engine must not be modified in any way apart
from with accessories and service kits developed
for it by Volvo Penta.

• No modifications to the exhaust pipes and air
supply ducts for the engine room (ventilation
ducts) may be undertaken as this may effect ex­haust emissions.

• Seals may only be broken by authorized person­nel.

IMPORTANT! Use only Volvo Penta Genuine

Parts.

Use of non-original AB Volvo Penta spare
parts will result in AB Volvo Penta being un­able to assume liability for the engine meet­ing engine certification requirements.

Any type of damage resulting from the use of
non-original Volvo Penta replacement parts for
the product will not be covered under any war­ranty provided by AB Volvo Penta.

5

Repair methods

The working methods described in the Service
Manual apply to work carried out in a workshop. The
engine has been removed from the boat and is
installed in an engine fixture. Unless otherwise stated
reconditioning work which can be carried out with the
engine in place follows the same working method.

Warning symbols occurring in the Workshop Manual
(for their meaning see Safety in formation)

NOTE!

are not in any way comprehensive since it is impossi­ble to predict every circumstance under which
service work or repairs may be carried out. For this
reason we can only highlight the risks that can arise
when work is carried out incorrectly in a well­equipped workshop using working methods and tools
developed by us.

All procedures for which there are Volvo Penta spe­cial tools in this Workshop Manual are carried out us­ing these. Special tools are developed to rationalize
working methods and make procedures as safe as
possible. It is therefore the responsibility of any per­son using tools or working methods other than the
ones recommended by us to ensure that there is no
danger of injury, damage or malfunction resulting
from these.

In some cases there may be special safety precau­tions and instructions for the use of tools and chemi­cals contained in this Workshop Manual. These spe­cial instructions should always be followed if there
are no separate instructions in the Workshop
Manual.

Certain elementary precautions and common sense
can prevent most risks arising. A clean workplace
and engine eliminates much of the danger of injury
and malfunction.

It is of the greatest importance that no dirt or foreign
particles get into the fuel system, lubrication system,
intake system, turbocharger, bearings and seals
when they are being worked on. The result can be
malfunction or a shorter operational life.

WARNING!

IMPORTANT!

Our joint responsibility

Each engine consists of many connected systems
and components. If a component deviates from its
technical specification the environmental impact of
an otherwise good engine may be increased
significantly. It is therefore vital that wear tolerances
are maintained, that systems that can be adjusted
are adjusted properly and that Volvo Penta Genuine
Parts as used. The engine Maintenance Schedule
must be followed.

Some systems, such as the components in the fuel
system, require special expertise and special testing
equipment for service and maintenance. Some com­ponents are sealed at the factory for environmental
reasons. No work should be carried out on seale d
components except by authorized personnel.

Bear in mind that most chemicals used on boats are
harmful to the environment if used incorrectly. Volvo
Penta recommends the use of biodegradable de­greasing agents for cleaning engine components, un­less otherwise stated in a workshop manual. Take
special care when working on-board, that oil and
waste is taken for destruction and is not accidentally
pumped into the environment with bilge water.

Tightening torques

Tightening torques for vital joints that must be tight­ened with a torque wrench are listed in work shop
manual ‘Technical Data”: “Tightening Torques” and
are contained in work descriptions in this Manual. All
torques apply for cleaned threads, screw heads and
mating surfaces. Torques apply for lightly oiled or dry
threads. If lubricants, locking fluid or sealing com­pound are required for a screwed joint this
information will be contained in the work description
and in “Tightening Torques’ Where no tightening
torque is stated for a joint use the general tightening
torques according to the tables below. The tightening
torques stated are a guide and the joint does not
have to be tightened using a torque wrench.

Dimension Tightening Torques
Nm lbt.ft

M5 6 4,4
M6 10 7,4
M8 25 18,4
M10 50 36,9
M12 80 59,0
M14 140 103,3

6

Tightening torques-protractor (angle)
tightening

Tightening using both a torque
setting and a protractor angle
requires that first the
recommended torque is applied
using a torque wrench and then
the recommended angle is
added according to the
protractor scale. Example: a
9Q0 protractor tightening
means that the joint is
tightened a further 1/4 turn in
one operation after the stated
tightening torque has been
applied.

Locknuts

Do not re-use lock nuts that have been removed dur­ing dismantling as they have reduced service life
when re-used - use new nuts when assembling or re­installing. For lock nuts with a plastic insert such as
Nylock® the tightening torque stated in the table is
reduced if the Nylock® nut has the same head height
as a standard hexagonal nut without plastic insert.
Reduce the tightening torque by 25% for bolt size 8
mm or larger. Where Nylock® nuts are higher, or of
the same height as a standard hexagonal nut, the
tightening torques given in the table apply.

Tolerance classes

Screws and nuts are divided into different strength
classes, the class is indicated by the number on the
bolt head. A high number indicates stronger material,
for example a bolt marked 10-9 indicates a higher
tolerance than one marked 8-8. It is therefore
important that bolts removed during the disassembly
of a bolted joint must be reinstalled in their original
position when assembling the joint, It a bolt must be
replaced check in the replacement parts catalogue to
make sure the correct bolt is used.

Sealants

A number of sealants and locking liquids are used on
the engines. The agents have varying properties and
are used for different types of jointing strengths, oper
ating temperature ranges, resistance to oil and other
chemicals and for the different materials and gap siz­es in the engines.

To ensure service work is correctly carried out it is
important that the correct sealant and locking fluid
type is used on the joint where the agents are re­quired.

In this Volvo Penta Service Manual the us er will find
that each section where these agents are appli ed in
production states which type was used on the
engine.

During service operations use the same agent or an
alternative from a different manufacturer.

Make sure that mating surfaces are dry and free from
oil, grease, paint and anti-corrosion agent before ap­plying sealant or locking fluid.

Always follow the manufacturer’s instructions for use
regarding; temperature range, curing time and any
other instructions for the product.

Two different basic types of agent are used on the
engine and these are:

RTV agent (Room temperature vulcanizing). Use for
gaskets, sealing gasket joints or coating gaskets.
RTV agent is clearly visible when a component has
been dismantled; old RTV must be removed before
the joint is resealed.

The following RTV agents are mentioned in the Serv­ice Manual: Loctite® 574, Volvo Penta 8408 79- 1,
Permatex®

No. 3, Volvo Penta P/N 1161099-5, Permatex® No.

77. Old sealant can be removed using methylated

spirits in all cases.
Anaerobic agents. These agents cure in an absence

of air. They are used when two solid parts, for exam­ple cast components, are installed face-to-face with­out a gasket. They are also commonly used to se­cure plugs, threads in stud bolts, cocks, o il pressure
switches and so on. The cured material is glass-like
and it is therefore colored to make it visible. Cured
anaerobic agents are extremely resistant to solvents
and the old agent cannot be removed. When
reinstalling the part is carefully degreased and then
new sealant is applied.

The following anaerobic agents are mentioned in the
Service Manual: Loctite® 572 (white), Loctite® 241
(blue).

NOTE! Loctite® is the registered trademark of Loctite Corporation,
Permatex® is the registered trademark of the Permatex
Corporation.

7

Presentation

MD6A

1. Recess for starting crank

2. Oil filling, engine

3. Sealed crankcase ventilation

4. Intake silencer

5. Connection, fuel inlet

6. Feed pump

7. Reduction reverse gear MS, red.

1.91:1

8. Control lever, reverse gear

9. Oil filling, reverse gear

10. Oil pressure contact

11. Lubricating oil filter

12. Start-generator

13. Fuel filter

14. Water-cooled exhaust manifold

15. Decompression handle

16. Injectors

17. Temperature sender

18. Cooling water outlet

19. Thermostat housing

20. Throttle lever

21. Stop lever

22. Fuel injection pump

23. Oil dipstick, engine

24. Fuel return line connection

25. Sea-water pump

26. Oil dipstick, reverse gear

8

MD7A

1. Oil dip-stick and oil filling, reverse gear

2. Cover, cooling water pump

3. Bleed-screw, fine filter

4. Fine filter

5. Decompression handle

6. Pressure pipe nut

7. Temperature sender

8. Injector

9. Thermostat housing

10. Oil filling, engine

11. Hand start

12. Cooling water drain, engine

13. Fuel injection pump

14. Oil dip-stick, engine

15. Cooling water drain, reverse gear

16. Air cleaner and intake silencer

17. Sender, rev, counter

18. Fuel pump (with hand pump)

19. Cooling water inlet, reduction gear

20. Oil drain, reverse gear, reduction gear

21. Warner, low oil pressure

22. Oil filter

9

Repair instructions

Drain the cooling water and oil from the engine. Then
clean the outside of the engine. Remove the rever s e
gear, 4 bolts.

Removal

1. Remove the air cleaner, disconnect the
alternator electric cables and the oil pressure
cable, remove the alternator and the drive belts.
Then remove the sea-water pump, the oil filter,
the fuel filter and the feed pump. (Look out for
fuel and oil splash.)

3. Remove the thermostat housing (2 bolts) and the
hose clamp under the housing. Take the
thermostat out of the exhaust manifold. Note the
small O-ring which seals against the exhaust
manifold.

2. Remove the injectors and pipes as well as the
leak-off oil pipe. Discard the sealing washers on
both sides of the leak-off oil pipe.

4. Remove the exhaust manifold (4 bolts).

10

5. Remove the rocker arm cover (2 nuts), the intake
manifold (4 bolts), the rocker arm (2 nuts) and
the cylinder head (9 bolts). Take care of the
washers.

6. Remove the cover on which the water pump is
mounted. NOTE! Two of the five bolts are
shorter than the other three and are placed
towards the centre of the engine. Take care of
the control bracket. Discard the old gasket.

7. a. (BOSCH pump) Disconnect the pipe from the
fuel filter and remove the nuts for the fuel
injection pump.

7. b. (CAV pump) Disconnect the pipe from the fuel
filter and remove the nuts for the fuel injection
pump.

8. Remove the nut which drives the water pump.
Use the flywheel as a counterhold. Remove the
fuel injection pump and the gear wheel.

11

9. Remove the timing gear cover. NOTE! The small
round cover on which the fuel pump is mounted
has bolts with 3 different lengths. The bolts for
the large casing has two lengths. The two bottom
bolts are shorter than the others. Carefully lever
loose the timing gear casing from its guide pins.
Discard the gasket.

11. Knock out the hand starter pin in the camshaft.
Remove the protective cover (2 bolts). NOTE!
Scrap the sealing ring and fit a new one.

10. Remove the flywheel. Remove the nut and use a
puller. The axle is tapered and provided with a
key. Use a counterhold when releasing the nut.

12. Remove the front cover behind the flywheel (11
bolts). Note the guide pins. Carefully tap all
round. Replace the gasket and the sealing ring.

12

13. Remove the sump as well as the nut and lock
washer for the camshaft. Use a counterhold on
the crankshaft.

15. Remove the bolt for the intermediate gear. Dis­card the sealing washer 1 under the bolt. Pull off
the intermediate gear.

14. Bend down the lock washer and release the bolt
securing the reverse gear flange to the
crankshaft. Use a counterhold. NOTE! Take care
of the key. Lever loose the rubber damper with a
screwdriver.

16. Check that the shaft pin 1 for the intermediate
gear is secure.

13