Mercury 25 TwoStroke, 30 TwoStroke Installation Manual

Operation

Maintenance

and

Installation

Manual

© 2017 Mercury Marine

25/30 TwoStroke

8M0133465 717 eng

eng

Welcome

You have selected one of the finest marine power packages available. It
incorporates numerous design features to ensure operating ease and durability.

With proper care and maintenance, you will enjoy using this product for many
boating seasons. To ensure maximum performance and carefree use, we ask
that you thoroughly read this manual.

The Operation and Maintenance Manual contains specific instructions for using
and maintaining your product. We suggest that this manual remain with the
product for ready reference whenever you are on the water.

Thank you for purchasing one of our products. We sincerely hope your boating
will be pleasant!

Mercury Marine, Fond du Lac, Wisconsin, U.S.A.

Name / function:

John Pfeifer, President,
Mercury Marine

Read This Manual Thoroughly

IMPORTANT: If you do not understand any portion of this manual, contact your
dealer. Your dealer can also provide a demonstration of actual starting and
operating procedures.

Notice

Throughout this publication, and on your power package, warnings, cautions,

and notices, accompanied by the International Hazard Symbol

!

, may be
used to alert the installer and user to special instructions concerning a
particular service or operation that may be hazardous if performed incorrectly
or carelessly. Observe them carefully.

These safety alerts alone cannot eliminate the hazards that they signal. Strict
compliance with these special instructions while performing the service, plus
common sense operation, are major accident prevention measures.

!

WARNING

Indicates a hazardous situation which, if not avoided, could result in death or
serious injury.

!

CAUTION

Indicates a hazardous situation which, if not avoided, could result in minor or
moderate injury.

eng i

NOTICE

Indicates a situation which, if not avoided, could result in engine or major
component failure.

IMPORTANT: Identifies information essential to the successful completion of
the task.

NOTE: Indicates information that helps in the understanding of a particular step
or action.

IMPORTANT: The operator (driver) is responsible for the correct and safe
operation of the boat, the equipment aboard, and the safety of all occupants
aboard. We strongly recommend that the operator read this Operation and
Maintenance Manual and thoroughly understand the operational instructions for
the power package and all related accessories before the boat is used.

!

WARNING

The engine exhaust from this product contains chemicals known to the state
of California to cause cancer, birth defects or other reproductive harm.

The serial numbers are the manufacturer’s keys to numerous engineering
details that apply to your Mercury Marine power package. When contacting
Mercury Marine about service, always specify model and serial numbers.

Descriptions and specifications contained herein were in effect at the time this
was approved for printing. Mercury Marine, whose policies are based on
continuous improvement, reserves the right to discontinue models at any time
or to change specifications or designs without notice and without incurring
obligation.

Warranty Message

The product you have purchased comes with a limited warranty from Mercury
Marine; the terms of the warranty are set forth in the Warranty Manual included
with the product. The Warranty Manual contains a description of what is
covered, what is not covered, the duration of coverage, how to best obtain
warranty coverage, important disclaimers and limitations of damages, and
other related information. Please review this important information.

Mercury Marine products are designed and manufactured to comply with our
own high quality standards, applicable industry standards and regulations, as
well as certain emissions regulations. At Mercury Marine every engine is
operated and tested before it is boxed for shipment to make sure that the
product is ready for use. In addition, certain Mercury Marine products are
tested in a controlled and monitored environment, for up to 10 hours of engine
run time, in order to verify and make a record of compliance with applicable
standards and regulations. All Mercury Marine product, sold as new, receives
the applicable limited warranty coverage, whether the engine participated in
one of the test programs described above or not.

ii eng

Copyright and Trademark Information

© MERCURY MARINE. All rights reserved. Reproduction in whole or in
part without permission is prohibited.

Alpha, Axius, Bravo One, Bravo Two, Bravo Three, GO BOLDLY., Circle M with
Waves Logo, K‑planes, Mariner, MerCathode, MerCruiser, Mercury, Mercury
with Waves Logo, Mercury Marine, Mercury Precision Parts, Mercury
Propellers, Mercury Racing, MotorGuide, OptiMax, Quicksilver, SeaCore,
Skyhook, SmartCraft, Sport‑Jet, Verado, VesselView, Zero Effort, Zeus, #1 On
the Water and We're Driven to Win are registered trademarks of Brunswick
Corporation. Pro XS is a trademark of Brunswick Corporation. Mercury Product
Protection is a registered service mark of Brunswick Corporation.

Identification Records

Please record the following applicable information:

Outboard

Engine Model and Horsepower

Engine Serial Number

Gear Ratio

Propeller Number Pitch Diameter

Hull Identification Number (HIN) Purchase Date

Boat Manufacturer Boat Model Length

Exhaust Gas Emissions Certification Number (Europe Only)

eng iii

eng iv

General Information

Boater's Responsibilities..................................................................................... 1

Before Operating Your Outboard........................................................................ 1

Boat Horsepower Capacity................................................................................. 1

High‑Speed and High‑Performance Boat Operation.......................................... 2

Outboard Remote Control Models...................................................................... 2

Remote Steering Notice......................................................................................3

Lanyard Stop Switch........................................................................................... 4

Protecting People in the Water........................................................................... 6

Passenger Safety Message ‑ Pontoon Boats and Deck Boats...........................7

Wave and Wake Jumping................................................................................... 8

Impact with Underwater Hazards........................................................................9

Exhaust Emissions........................................................................................... 11

Selecting Accessories for Your Outboard......................................................... 13

Safe Boating Recommendations...................................................................... 13

Recording Serial Number................................................................................. 15

Model Year Production Code............................................................................16

25/30 Specifications..........................................................................................17

Components..................................................................................................... 18

Transporting

Trailering Boat/Outboard.................................................................................. 24

Removing the Motor ........................................................................................ 24

Transporting Portable Fuel Tanks.................................................................... 25

Fuel and Oil

Fuel Requirements........................................................................................... 27

Oil Recommendation........................................................................................ 28

Mixing Fuel and Oil........................................................................................... 28

Filling Fuel Tank............................................................................................... 29

Features and Controls

Remote Control Features................................................................................. 30

Tilting Outboard ............................................................................................... 30

Shallow Water Operation.................................................................................. 31

Trim Adjustment................................................................................................32

Steering Friction Adjustment.............................................................................33

Trim Tab Adjustment........................................................................................ 34

eng v

Operation

Prestarting Check List.......................................................................................36

Operating in Freezing Temperatures................................................................ 36

Operating in Saltwater or Polluted Water......................................................... 36

Operating at High Elevations............................................................................ 37

Engine Break‑in Procedure...............................................................................37

Starting the Engine........................................................................................... 38

Warm‑Up.......................................................................................................... 44

Gear Shifting..................................................................................................... 44

Stopping the Engine......................................................................................... 47

Emergency Starting.......................................................................................... 48

Maintenance

Cleaning Care Recommendations.................................................................... 50

Inspection and Maintenance Schedule ............................................................ 51

Flushing the Cooling System............................................................................ 52

Top Cowl Removal and Installation.................................................................. 54

Battery Inspection ............................................................................................ 55

Fuel System...................................................................................................... 55

Fuse Replacement ‑ Electric Start Remote Control Models............................. 56

Corrosion Control Anode.................................................................................. 56

Propeller Replacement..................................................................................... 57

Spark Plug Inspection and Replacement..........................................................61

Lubrication Points............................................................................................. 62

Gearcase Lubricant.......................................................................................... 62

Submerged Outboard....................................................................................... 64

Storage

Storage Preparation..........................................................................................65

Protecting External Outboard Components...................................................... 65

Protecting Internal Engine Components........................................................... 66

Gearcase.......................................................................................................... 66

Positioning Outboard for Storage..................................................................... 66

Battery Storage................................................................................................. 66

vi eng

Troubleshooting

Starter Motor Will Not Crank the Engine (Electric Start Models)...................... 67

Engine Will Not Start.........................................................................................67

Engine Runs Erratically.................................................................................... 67

Performance Loss.............................................................................................68

Battery Will Not Hold Charge............................................................................ 68

Engine Installation

Mercury Marine Validated Engine Mounting Hardware.................................... 69

Installing Outboard............................................................................................69

Installing the Remote Control Device .............................................................. 72

Attaching the Steering Link Rod....................................................................... 82

Battery Installation ........................................................................................... 83

Propeller Selection............................................................................................84

Associated Parts

Associated Parts............................................................................................... 86

Accessories

Accessories...................................................................................................... 87

Wiring Diagrams

Wiring Diagrams............................................................................................... 92

Owner Service Assistance

Service Assistance......................................................................................... 100

Ordering Literature..........................................................................................102

Maintenance Log

Maintenance Log............................................................................................ 104

eng vii

eng viii

Boater's Responsibilities

The operator (driver) is responsible for the correct and safe operation of the
boat and the safety of its occupants and general public. It is strongly
recommended that each operator read and understand this entire manual
before operating the outboard.

Be sure that at least one additional person onboard is instructed in the basics
of starting and operating the outboard and boat handling in case the driver is
unable to operate the boat.

Before Operating Your Outboard

Read this manual carefully. Learn how to operate your outboard properly. If you
have any questions, contact your dealer.

Safety and operating information that is practiced, along with using good
common sense, can help prevent personal injury and product damage.

This manual as well as safety labels posted on the outboard use the following
safety alerts to draw your attention to special safety instructions that should be
followed.

!

WARNING

Indicates a hazardous situation which, if not avoided, could result in death or
serious injury.

!

CAUTION

Indicates a hazardous situation which, if not avoided, could result in minor or
moderate injury.

NOTICE

Indicates a situation which, if not avoided, could result in engine or major
component failure.

Boat Horsepower Capacity

!

WARNING

Exceeding the boat's maximum horsepower rating can cause serious injury
or death. Overpowering the boat can affect boat control and flotation
characteristics or break the transom. Do not install an engine that exceeds
the boat's maximum power rating.

GENERAL INFORMATION

eng 1

Do not overpower or overload your boat. Most boats will carry a required
capacity plate indicating the maximum acceptable power and load as
determined by the manufacturer following certain federal guidelines. If in doubt,
contact your dealer or the boat manufacturer.

U.S. COAST GUARD CAP ACITY

MAXIMUM HORSEPOWER XXX

MAXIMUM PERSON
CAPACITY (POUNDS)

XXX

MAXIMUM WEIGHT
CAPACITY

XXX

26777

High‑Speed and High‑Performance Boat Operation

If your outboard is to be used on a high‑speed or high‑performance boat with
which you are unfamiliar, we recommend that you do not operate it at its high
speed capability without first requesting an initial orientation and familiarization
demonstration ride with your dealer or an operator experienced with your boat/
outboard combination. For additional information, obtain a copy of our
Hi‑Performance Boat Operation booklet from your dealer, distributor, or
Mercury Marine.

Outboard Remote Control Models

The remote control connected to your outboard must be equipped with a start
in neutral only protection device. This prevents the engine from starting when
the shift is actuated in any position other than neutral.

GENERAL INFORMATION

2 eng

!

WARNING

Starting the engine with the drive in gear can cause serious injury or death.
Never operate a boat that does not have a neutral‑safety‑protection device.

37882

Remote Steering Notice

!

WARNING

Improper fasteners or improper installation procedures can result in
loosening or disengagement of the steering link rod. This can cause a
sudden, unexpected loss of boat control, resulting in serious injury or death
due to occupants being thrown within or out of the boat. Always use required
components and follow instructions and torque procedures.

The steering link rod that connects the steering cable to the engine must be
fastened utilizing self‑locking nuts. These self‑locking nuts must never be
replaced with common nuts (nonlocking) as they will work loose and vibrate off,
freeing the link rod to disengage.

a - Self‑locking nuts

a

a

28984

GENERAL INFORMATION

eng 3

Lanyard Stop Switch

The purpose of a lanyard stop switch is to turn off the engine when the operator
moves far enough away from the operator's position (as in accidental ejection
from the operator's position) to activate the switch. Tiller handle outboards and
some remote control units are equipped with a lanyard stop switch. A lanyard
stop switch can be installed as an accessory ‑ generally on the dashboard or
side adjacent to the operator's position.

A decal near the lanyard stop switch is a visual reminder for the operator to
attach the lanyard to their personal flotation device (PFD) or wrist.

The lanyard cord is usually 122–152 cm (4–5 feet) in length when stretched out,
with an element on one end made to be inserted into the switch and a clip on
the other end for attaching to the operator's PFD or wrist. The lanyard is coiled
to make its at‑rest condition as short as possible to minimize the likelihood of
lanyard entanglement with nearby objects. Its stretched‑out length is made to
minimize the likelihood of accidental activation should the operator choose to
move around in an area close to the normal operator's position. If it is desired
to have a shorter lanyard, wrap the lanyard around the operator's wrist or leg,
or tie a knot in the lanyard.

a - Lanyard cord clip
b - Lanyard decal
c - Lanyard stop switch

Read the following Safety Information before proceeding.

c

a

b

53910

OFF

RUN

ATTACH LANYARD

GENERAL INFORMATION

4 eng

Important Safety Information: The purpose of a lanyard stop switch is to stop
the engine when the operator moves far enough away from the operator's
position to activate the switch. This would occur if the operator accidentally falls
overboard or moves within the boat a sufficient distance from the operator's
position. Falling overboard and accidental ejections are more likely to occur in
certain types of boats such as low sided inflatables, bass boats, high
performance boats, and light, sensitive handling fishing boats operated by a
hand tiller. Falling overboard and accidental ejections are also likely to occur as
a result of poor operating practices such as sitting on the back of the seat or
gunwale at planing speeds, standing at planing speeds, sitting on elevated
fishing boat decks, operating at planing speeds in shallow or obstacle infested
waters, releasing your grip on a steering wheel or tiller handle that is pulling in
one direction, drinking alcohol or consuming drugs, or daring high speed boat
maneuvers.

While activation of the lanyard stop switch will stop the engine immediately, a
boat will continue to coast for some distance depending upon the velocity and
degree of any turn at shut down. However, the boat will not complete a full
circle. While the boat is coasting, it can cause injury to anyone in the boat's
path as seriously as the boat would when under power.

We strongly recommend that other occupants be instructed on proper starting
and operating procedures should they be required to operate the engine in an
emergency (if the operator is accidentally ejected).

!

WARNING

If the operator falls out of the boat, stop the engine immediately to reduce the
possibility of serious injury or death from being struck by the boat. Always
properly connect the operator to the stop switch using a lanyard.

!

WARNING

Avoid serious injury or death from deceleration forces resulting from
accidental or unintended stop switch activation. The boat operator should
never leave the operator's station without first disconnecting the stop switch
lanyard from the operator.

Accidental or unintended activation of the switch during normal operation is
also a possibility. This could cause any, or all, of the following potentially
hazardous situations:

• Occupants could be thrown forward due to unexpected loss of forward
motion ‑ a particular concern for passengers in the front of the boat who
could be ejected over the bow and possibly struck by the gearcase or
propeller.

• Loss of power and directional control in heavy seas, strong current, or
high winds.

• Loss of control when docking.

GENERAL INFORMATION

eng 5

KEEP THE LANYARD STOP SWITCH AND LANYARD CORD IN GOOD
OPERATING CONDITION

Before each use, check to ensure the lanyard stop switch works properly. Start
the engine and stop it by pulling the lanyard cord. If the engine does not stop,
have the switch repaired before operating the boat.

Before each use, visually inspect the lanyard cord to ensure it is in good
working condition and that there are no breaks, cuts, or wear to the cord.
Check that the clips on the ends of the cord are in good condition. Replace any
damaged or worn lanyard cords.

Protecting People in the Water

WHILE YOU ARE CRUISING

It is very difficult for a person standing or floating in the water to take quick
action to avoid a boat heading in his/her direction, even at slow speed.

21604

Always slow down and exercise extreme caution any time you are boating in an
area where there might be people in the water.

Whenever a boat is moving (coasting) and the outboard gear shift is in neutral
position, there is sufficient force by the water on the propeller to cause the
propeller to rotate. This neutral propeller rotation can cause serious injury.

WHILE THE BOAT IS STATIONARY

!

WARNING

A spinning propeller, a moving boat, or any solid device attached to the boat
can cause serious injury or death to swimmers. Stop the engine immediately
whenever anyone in the water is near your boat.

Shift the outboard into neutral and shut off the engine before allowing people to
swim or be in the water near your boat.

GENERAL INFORMATION

6 eng

Passenger Safety Message ‑ Pontoon Boats and Deck Boats

Whenever the boat is in motion, observe the location of all passengers. Do not
allow any passengers to stand or use seats other than those designated for
traveling faster than idle speed. A sudden reduction in boat speed, such as
plunging into a large wave or wake, a sudden throttle reduction, or a sharp
change of boat direction, could throw them over the front of the boat. Falling
over the front of the boat between the two pontoons will position them to be run
over by the outboard.

BOATS HAVING AN OPEN FRONT DECK

No one should ever be on the deck in front of the fence while the boat is in
motion. Keep all passengers behind the front fence or enclosure.

Persons on the front deck could easily be thrown overboard or persons
dangling their feet over the front edge could get their legs caught by a wave
and pulled into the water.

26782

!

WARNING

Sitting or standing in an area of the boat not designed for passengers at
speeds above idle can cause serious injury or death. Stay back from the front
end of deck boats or raised platforms and remain seated while the boat is in
motion.

BOATS WITH FRONT MOUNTED, RAISED PEDESTAL FISHING SEATS

Elevated fishing seats are not intended for use when the boat is traveling faster
than idle or trolling speed. Sit only in seats designated for traveling at faster
speeds.

GENERAL INFORMATION

eng 7

Any unexpected, sudden reduction in boat speed could result in the elevated
passenger falling over the front of the boat.

26783

Wave and Wake Jumping

Operating recreational boats over waves and wake is a natural part of boating.
However, when this activity is done with sufficient speed to force the boat hull
partially or completely out of the water, certain hazards arise, particularly when
the boat enters the water.

26784

The primary concern is the boat changing direction while in the midst of the
jump. In such case, the landing may cause the boat to veer violently in a new
direction. Such a sharp change in direction can cause occupants to be thrown
out of their seats, or out of the boat.

!

WARNING

Wave or wake jumping can cause serious injury or death from occupants
being thrown within or out of the boat. Avoid wave or wake jumping whenever
possible.

There is another less common hazardous result from allowing your boat to
launch off a wave or wake. If the bow of your boat pitches down far enough
while airborne, upon water contact it may penetrate under the water surface
and submarine for an instant. This will bring the boat to a nearly instantaneous
stop and can send the occupants flying forward. The boat may also steer
sharply to one side.

GENERAL INFORMATION

8 eng

Impact with Underwater Hazards

Your outboard may be equipped with a hydraulic trim and tilt system that also
contains a shock absorbing feature. This feature helps the outboard withstand
damage in the case of impact with an underwater object at low to moderate
speeds. At higher speeds, the force of the impact may exceed the system’s
ability to absorb the energy of the impact and cause serious product damage.

No impact protection exists while in reverse. Use extreme caution when
operating in reverse to avoid striking underwater objects.

Reduce speed and proceed with caution whenever you drive a boat in shallow
water areas or in areas where you suspect underwater obstacles may exist that
could be struck by the outboard or the boat bottom. The most significant

action you can take to help reduce injury or impact damage from striking
a floating or underwater object is to control the boat speed. Under these
conditions, boat speed should be kept to the minimum planing speed,
typically 24 to 40 km/h (15 to 25 mph).

26785

!

WARNING

Avoid serious injury or death from all or part of an outboard or drive unit
coming into the boat after striking a floating or underwater object. When
operating in waters where objects may be at the surface or just under the
surface of the water, reduce your speed and keep a vigilant lookout.

Examples of objects that can cause engine damage are dredging pipes,
bridge supports, wing dams, trees, stumps, and rocks.

Striking a floating or underwater object could result in any of an infinite number
of situations. Some of these situations could yield the following:

• Part of the outboard or the entire outboard could break loose and fly into
the boat.

• The boat could move suddenly in a new direction. A sharp change in
direction can cause occupants to be thrown out of their seats or out of the
boat.

• The boat's speed could rapidly reduce. This will cause occupants to be
thrown forward or even out of the boat.

GENERAL INFORMATION

eng 9

• The outboard or boat could sustain impact damage.

After striking a submerged object, stop the engine as soon as possible and
inspect it for any broken or loose parts. If damage is present or suspected, the
outboard should be taken to an authorized dealer for a thorough inspection and
necessary repair.

The boat should also be checked for any hull fractures, transom fractures, or
water leaks. If water leaks are discovered after an impact, immediately activate
the bilge pump.

Operating a damaged outboard could cause additional damage to other parts
of the outboard or could affect control of the boat. If continued running is
necessary, do so at greatly reduced speeds.

!

WARNING

Operating a boat or engine with impact damage can result in product
damage, serious injury, or death. If the vessel experiences any form of
impact, have an authorized Mercury Marine dealer inspect and repair the
vessel or power package.

SAFETY INSTRUCTIONS FOR HAND-TILLED OUTBOARDS

No person or cargo should occupy the area directly in front of the outboard
while the boat is in motion. If an underwater obstacle is struck, the outboard will
tilt up and could seriously injure anyone occupying this area.

Models with Clamp Screws:

Some outboards come with transom bracket clamp screws. The use of clamp
bracket screws alone is insufficient to properly and safely secure the outboard
to the transom. Proper installation of the outboard includes bolting the engine to
the boat through the transom. Refer to Engine Installation ‑ Installing
Outboard for more complete installation information.

!

WARNING

Failure to correctly fasten the outboard could result in the outboard propelling
off the boat transom resulting in property damage, serious injury, or death.
Before operation, the outboard must be correctly installed with the required
mounting hardware.

GENERAL INFORMATION

10 eng

This product must be secured to the transom with the required mounting
hardware. If the outboard strikes an underwater object, the required mounting
hardware prevents the outboard from propelling off the transom. A decal on the
swivel bracket reminds the installer of the potential hazard.

Avoid serious injury
or death. Secure
engine to transom
with bolts.

WARNING

37-896853-007

52375

Exhaust Emissions

BE ALERT TO CARBON MONOXIDE POISONING

Carbon monoxide (CO) is a deadly gas that is present in the exhaust fumes of
all internal combustion engines, including the engines that propel boats, and
the generators that power boat accessories. By itself, CO is odorless, colorless,
and tasteless, but if you can smell or taste engine exhaust, you are inhaling
CO.

Early symptoms of carbon monoxide poisoning, which are similar to the
symptoms of seasickness and intoxication, include headache, dizziness,
drowsiness, and nausea.

!

WARNING

Inhaling engine exhaust gases can result in carbon monoxide poisoning,
which can lead to unconsciousness, brain damage, or death. Avoid exposure
to carbon monoxide.

Stay clear from exhaust areas when engine is running. Keep the boat
well‑ventilated while at rest or underway.

STAY CLEAR OF EXHAUST AREAS

41127

co

co

co

co

co

co

co

co

co

co

co

co

co

co

co

co

co

co

co

co

GENERAL INFORMATION

eng 11

Engine exhaust gases contain harmful carbon monoxide. Avoid areas of
concentrated engine exhaust gases. When engines are running, keep
swimmers away from the boat, and do not sit, lie, or stand on swim platforms or
boarding ladders. While underway, do not allow passengers to be positioned
immediately behind the boat (platform dragging, teak/body surfing). This
dangerous practice not only places a person in an area of high engine exhaust
concentration, but also subjects them to the possibility of injury from the boat
propeller.

GOOD VENTILATION

Ventilate the passenger area, open side curtains or forward hatches to remove
fumes.

Example of desired air flow through the boat:

21622

POOR VENTILATION

Under certain running and/or wind conditions, permanently enclosed or canvas
enclosed cabins or cockpits with insufficient ventilation may draw in carbon
monoxide. Install one or more carbon monoxide detectors in your boat.

Although the occurrence is rare, on a very calm day, swimmers and
passengers in an open area of a stationary boat that contains, or is near, a
running engine may be exposed to a hazardous level of carbon monoxide.

1. Examples of poor ventilation while the boat is stationary:

a - Operating the engine when the boat is moored in a confined space
b - Mooring close to another boat that has its engine operating

21626

a

b

GENERAL INFORMATION

12 eng

2. Examples of poor ventilation while the boat is moving:

a - Operating the boat with the trim angle of the bow too high
b - Operating the boat with no forward hatches open (station wagon effect)

Selecting Accessories for Your Outboard

Genuine Mercury Precision or Quicksilver Accessories have been specifically
designed and tested for your outboard. These accessories are available from
Mercury Marine dealers.

IMPORTANT: Check with your dealer before installing accessories. The misuse
of approved accessories or the use of nonapproved accessories can damage
the product.

Some accessories not manufactured or sold by Mercury Marine are not
designed to be safely used with your outboard or outboard operating system.
Acquire and read the installation, operation and maintenance manuals for all
your selected accessories.

Safe Boating Recommendations

To safely enjoy the waterways, familiarize yourself with local and all other
governmental boating regulations and restrictions and consider the following
suggestions.

Know and obey all nautical rules and laws of the waterways.

• We recommend that all powerboat operators complete a boating safety
course. In the U.S., the U.S. Coast Guard Auxiliary, the Power Squadron,
the Red Cross, and your state or provincial boating law enforcement
agency provide courses. For more information in the U.S., call the Boat
U.S. Foundation at 1‑800‑336‑BOAT (2628).

Perform safety checks and required maintenance.

• Follow a regular schedule and ensure that all repairs are properly made.

Check safety equipment onboard.

• Here are some suggestions of the types of safety equipment to carry
when boating:

Approved fire extinguishers

Signal devices: flashlight, rockets or flares, flag, and whistle or horn

Tools necessary for minor repairs

a

b

21628

GENERAL INFORMATION

eng 13

Anchor and extra anchor line

Manual bilge pump and extra drain plugs

Drinking water

Radio

Paddle or oar

Spare propeller, thrust hubs, and an appropriate wrench

First aid kit and instructions

Waterproof storage containers

Spare operating equipment, batteries, bulbs, and fuses

Compass and map or chart of the area

Personal flotation device (one per person onboard)

Watch for signs of weather change and avoid foul weather and rough‑sea
boating.

Tell someone where you are going and when you expect to return.

Passenger boarding.

• Stop the engine whenever passengers are boarding, unloading, or are
near the back (stern) of the boat. Shifting the drive unit into neutral is not
sufficient.

Use personal flotation devices.

• Federal law requires that there be a U.S. Coast Guard‑approved life
jacket (personal flotation device), correctly sized and readily accessible
for every person onboard, plus a throwable cushion or ring. We strongly
advise that everyone wear a life jacket at all times while in the boat.

Prepare other boat operators.

• Instruct at least one person onboard in the basics of starting and
operating the engine and boat handling in case the driver becomes
disabled or falls overboard.

Do not overload your boat.

• Most boats are rated and certified for maximum load (weight) capacities
(refer to your boat's capacity plate). Know your boat's operating and
loading limitations. Know if your boat will float if it is full of water. When in
doubt, contact your authorized Mercury Marine dealer or the boat
manufacturer.

Ensure that everyone in the boat is properly seated.

GENERAL INFORMATION

14 eng

• Do not allow anyone to sit or ride on any part of the boat that was not
intended for such use. This includes the backs of seats, gunwales,
transom, bow, decks, raised fishing seats, and any rotating fishing seat.
Passengers should not sit or ride anywhere that sudden unexpected
acceleration, sudden stopping, unexpected loss of boat control, or sudden
boat movement could cause a person to be thrown overboard or into the
boat. Ensure that all passengers have a proper seat and are in it before
any boat movement.

Never operate a boat while under the influence of alcohol or drugs. It is
the law.

• Alcohol or drugs can impair your judgment and greatly reduce your ability
to react quickly.

Know your boating area and avoid hazardous locations.

Be alert.

• The operator of the boat is responsible by law to maintain a proper
lookout by sight and hearing. The operator must have an unobstructed
view particularly to the front. No passengers, load, or fishing seats should
block the operator's view when the boat is above idle or planing transition
speed. Watch out for others, the water, and your wake.

Never drive your boat directly behind a water‑skier.

• Your boat traveling at 40 km/h (25 mph) will overtake a fallen skier who is
61 m (200 ft) in front of you in five seconds.

Watch fallen skiers.

• When using your boat for waterskiing or similar activities, always keep a
fallen or down skier on the operator's side of the boat while returning to
attend to the skier. The operator should always have the down skier in
sight and never back up to the skier or anyone in the water.

Report accidents.

• Boat operators are required by law to file a boating accident report with
their state boating law enforcement agency when their boat is involved in
certain boating accidents. A boating accident must be reported if 1) there
is loss of life or probable loss of life, 2) there is personal injury requiring
medical treatment beyond first aid, 3) there is damage to boats or other
property where the damage value exceeds $500.00, or 4) there is
complete loss of the boat. Seek further assistance from local law
enforcement.

Recording Serial Number

It is important to record the serial number and other important information for
future reference.

Please record the serial number of the engine as indicated (on the lower engine
cover and the cylinder block) in the space below. This number will come in
handy in the event of theft and it can help you to quickly identify the product
type.

GENERAL INFORMATION

eng 15

Serial number:
Model year:
Model designation:
Year manufactured:
Certified Europe Insignia (as applicable):

Model Year Production Code

The serial number decal lists the year of manufacture as an alpha code. This
code can be deciphered into a corresponding number utilizing the following
table.

XXXXXXXXX

XXXXXXXX

XXXX

AG

62972

Serial number decal alpha code

Model Year Manufactured Code
Alpha Production Code A B C D E F G H K X
Corresponding Number 1 2 3 4 5 6 7 8 9 0

Examples:

• XX = 2000

• HK = 2089

• AG = 2017

GENERAL INFORMATION

16 eng

25/30 Specifications

Model 25M 30M 30EH 30E

Overall length 884 mm (34.8 in.)

600 mm (23.6

in.)
Overall width 430 mm (16.9 in.) 355 mm (14 in.)
Overall height S: 1124 mm (44.3 in.) ‑ L: 1251 mm (49.3 in.)
Transom height S: 435 mm (17.1 in.) ‑ L: 562 mm (22.1 in.)

Weight 51 kg (112 lb)

55 kg

(121 lb)

54 kg (119 lb)

Max output HP (kW) 25 (18.4) 30 (22.1)

Full throttle RPM

5000–

6000

5150–5850

Fuel consumption 13 L/h
Number of cylinders 2

Piston displacement

430 cc (26.2 in3)
Cylinder bore 68 mm (2.68 in.)
Piston stroke 59 mm (2.32 in.)
Exhaust system Through hub exhaust
Cooling system Water‑cooled
Starting system Manual Electric/Manual

Battery rating

Minimum reserve capacity rating of 100 minutes and

350 cold cranking amps (CCA)
Ignition CD ignition
Spark plug NGK B7HS‑10 or Champion L82C‑NGK BPR7HS‑10
Spark plug gap 1.0 mm (0.035 in.)
Alternator 12 V, 80 W, 6.7 amps
Fuel mixing ratio 50:1 (Quicksilver TC‑W2 or TC‑W3 2‑Cycle)
Fuel tank capacities 25 L (6.6 US gal)
Gear reduction ratio 1.92:1
Gear oil Quicksilver Gear Lube Premium Blend
Gear oil volume 280 ml (9.5 fl oz)

GENERAL INFORMATION

eng 17

Components

37417

1

2

3

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

4

5

GENERAL INFORMATION

18 eng

MH models

1 - Tilt handle
2 - Upper cowl
3 - Water pump indicator hole
4 - Water plug
5 - Reverse lock lever
6 - Driveshaft housing
7 - Anti‑ventilation plate
8 - Trim tab
9 - Secondary water intake
10 - Propeller
11 - Starter rope handle
12 - Shift lever
13 - Throttle grip
14 - Clamp screw
15 - Clamp bracket
16 - Trim position pin
17 - Upper oil plug
18 - Cooling water intake
19 - Lower oil plug
20 - Connector B
21 - Stop switch
22 - Choke knob
23 - Fuel tank
24 - Primer valve
25 - Fuel connector
26 - Fuel tank cap
27 - Air vent screw
28 - Fuel pickup elbow

GENERAL INFORMATION

eng 19

37461

26

27

28

29

30

25

1

2

3

4

5

6

7

8

9

10

11

12

15

16

14

18

19

20

13

21

22

23

24

17

GENERAL INFORMATION

20 eng

EH models

1 - Tilt handle
2 - Upper cowl
3 - Water pump indicator hole
4 - Water plug
5 - Reverse lock lever
6 - Driveshaft housing
7 - Anti‑ventilation plate
8 - Trim tab
9 - Secondary water intake
10 - Propeller
11 - Starter rope handle
12 - Shift lever
13 - Throttle grip
14 - Clamp screw
15 - Clamp bracket
16 - Trim position pin
17 - Battery cable
18 - Upper oil plug
19 - Cooling water intake
20 - Lower oil plug
21 - Connector B
22 - Main switch
23 - Stop switch
24 - Choke knob
25 - Fuel tank
26 - Primer valve
27 - Fuel connector
28 - Fuel tank cap
29 - Air vent screw
30 - Fuel pickup elbow

GENERAL INFORMATION

eng 21

37463

26

27

28

29

30

25

1

2

3

4

5

6

7

8

9

10

11

12

14

15

13

17

18

19

20

16

21

22

23

24

GENERAL INFORMATION

22 eng

E models

1 - Tilt handle
2 - Upper cowl
3 - Water pump indicator hole
4 - Water plug
5 - Reverse lock lever
6 - Driveshaft housing
7 - Anti‑ventilation plate
8 - Trim tab
9 - Secondary water intake
10 - Propeller
11 - Starter rope handle
12 - Shift lever
13 - Clamp screw
14 - Clamp bracket
15 - Trim position pin
16 - Battery cable
17 - Upper oil plug
18 - Cooling water intake
19 - Lower oil plug
20 - Connector B
21 - Remote control box
22 - Main switch
23 - Stop switch
24 - Cord assembly
25 - Fuel tank
26 - Primer valve
27 - Fuel connector
28 - Fuel tank cap
29 - Air vent screw
30 - Fuel pickup elbow

GENERAL INFORMATION

eng 23

Trailering Boat/Outboard

The boat should be trailered with the outboard tilted down in a vertical
operating position.

IMPORTANT: The tilt lock and shallow water drive feature (tiller handle models)
on the outboard are not intended to support the outboard in the tilted position
when trailering.

If additional ground clearance is required, the outboard should be tilted up
using an accessory outboard support device. Refer to your local dealer for
recommendations. Additional clearance may be required for railroad crossings,
driveways, and trailer bouncing.

Shift the outboard to forward gear. This prevents the propeller from spinning
freely.

Removing the Motor

1. Stop the engine.

2. Disconnect the fuel connector from the motor.

37252

3. Remove the motor from the hull and completely drain the water from the
outboard.

TRANSPORTING

24 eng

4. Rest the motor on the ground with the clamp screw handles facing
upward.

37884

Transporting Portable Fuel Tanks

!

WARNING

Avoid serious injury or death from a gasoline fire or explosion. Follow the
transporting instructions supplied with the portable fuel tank. Transport the
fuel tank in a well ventilated area away from open flame or sparks.

MANUAL VENTING TYPE FUEL TANK

Close the fuel tank air vent when transporting tank. This will prevent escape of
fuel or vapors from tank.

26793

AUTO-VENTING TYPE FUEL TANK

1. Disconnect the remote fuel line from tank. This will close the air vent and
prevent escape of fuel or vapors from tank.

TRANSPORTING

eng 25

2. Install tether cap over the fuel line connector stem. This will protect the
connector stem from being accidentally pushed‑in, allowing fuel or vapor
to escape.

a - Connector stem
b - Tether cap

F

a

b

26794

TRANSPORTING

26 eng

Fuel Requirements

IMPORTANT: Use of improper gasoline can damage your engine. Engine
damage resulting from the use of improper gasoline is considered misuse
of the engine and will not be covered under the limited warranty.

FUEL RATINGS

Mercury outboard engines will operate satisfactorily with any major brand of
unleaded gasoline that meets the following specifications:

USA and Canada ‑ A posted pump octane rating of 87 (R+M)/2, minimum, for
most models. Premium gasoline 91 (R+M)/2 octane is also acceptable for most
models. Do not use leaded gasoline.

Outside USA and Canada ‑ A posted pump octane rating of 91 RON,
minimum, for most models. Premium gasoline (95 RON) is also acceptable for
all models. Do not use leaded gasoline.

USING REFORMULATED (OXYGENATED) GASOLINE (USA ONLY)

Reformulated gasoline is required in certain areas of the USA and is
acceptable for use in your Mercury Marine engine. The only oxygenate
currently in use in the USA is alcohol (ethanol, methanol, or butanol).

GASOLINE CONTAINING ALCOHOL

Bu16 Butanol Fuel Blends

Fuel blends of up to 16.1% butanol (Bu16) that meet the published Mercury
Marine fuel rating requirements are an acceptable substitute for unleaded
gasoline. Contact your boat manufacturer for specific recommendations on
your boat's fuel system components (fuel tanks, fuel lines, and fittings).

Methanol and Ethanol Fuel Blends

IMPORTANT: The fuel system components on your Mercury Marine engine will
withstand up to 10% alcohol (methanol or ethanol) content in the gasoline. Your
boat's fuel system may not be capable of withstanding the same percentage of
alcohol. Contact your boat manufacturer for specific recommendations on your
boat's fuel system components (fuel tanks, fuel lines, and fittings).

Be aware that gasoline containing methanol or ethanol may cause increased:

• Corrosion of metal parts

• Deterioration of rubber or plastic parts

• Fuel permeation through the rubber fuel lines

• Likelihood of phase separation (water and alcohol separating from the
gasoline in the fuel tank)

FUEL AND OIL

eng 27

!

WARNING

Fuel leakage is a fire or explosion hazard, which can cause serious injury or
death. Periodically inspect all fuel system components for leaks, softening,
hardening, swelling, or corrosion, particularly after storage. Any sign of
leakage or deterioration requires replacement before further engine
operation.

IMPORTANT: If you use gasoline that contains or might contain methanol or
ethanol, you must increase the frequency of inspection for leaks and
abnormalities.

IMPORTANT: When operating a Mercury Marine engine on gasoline containing
methanol or ethanol, do not store the gasoline in the fuel tank for long periods.
Cars normally consume these blended fuels before they can absorb enough
moisture to cause trouble; boats often sit idle long enough for phase separation
to take place. Internal corrosion may occur during storage if alcohol has
washed protective oil films from internal components.

Oil Recommendation

Recommended Oil

Mercury or Quicksilver Premium 2‑Cycle TC‑W3
Outboard Oil

IMPORTANT: Oil must be NMMA certified TC‑W3 2‑Cycle oil.
Mercury or Quicksilver Premium TC‑W3 2‑Cycle oil is recommended for this

engine. For added protection and lubrication, Mercury or Quicksilver Premium
Plus TC‑W3 2‑Cycle oil is recommended. If Mercury or Quicksilver outboard oil
is not available, substitute another brand of 2‑cycle outboard oil that is NMMA
Certified TC‑W3. Severe engine damage may result from use of an inferior oil.

Mixing Fuel and Oil

Use a 25:1 (4%) gasoline/oil mixture in the first tank of fuel.
After the break‑in fuel mixture is used up, use a 50:1 (2%) gasoline/oil mixture.

Refer to the table (following) for mixing ratios.

GASOLINE/OIL MIXING RATIO CHART

GASOLINE/OIL MIXING RATIO CHART

Gas/Oil Ratio 3.8 liters (1 gal) gas 11.5 liters (3 gal) gas 23 liters (6 gal) gas

25:1 (4%)

148 ml (5 fl oz) oil 473 ml (16 fl oz) oil 946 ml (32 fl oz) oil

50:1 (2%)

89 ml (3 fl oz) oil 237 ml (8 fl oz) oil 473 ml (16 fl oz) oil

MIXING PROCEDURE

Pour the full amount of oil along with approximately one gallon of gasoline into
an approved container. Shake the two together until they are thoroughly mixed.
Add the remainder of gasoline and shake container to ensure mixing.

FUEL AND OIL

28 eng

Filling Fuel Tank

!

WARNING

Avoid serious injury or death from a gasoline fire or explosion. Use caution
when filling fuel tanks. Always stop the engine and do not smoke or allow
open flames or sparks in the area while filling fuel tanks.

Fill fuel tanks outdoors away from heat, sparks, and open flames.
Always stop engine before refilling tanks.
Do not completely fill the fuel tanks. Leave approximately 10% of the tank

volume unfilled. Fuel will expand in volume as its temperature rises and can
leak under pressure if the tank is completely filled.

FILLING PERMANENTLY INSTALLED TANKS

Slowly pour the correct amount of oil along with gasoline as the tank is being
filled.

FILLING PORTABLE FUEL TANKS

Remove the portable fuel tanks from the boat to refill them.
Pour the full amount of oil, along with one gallon of gasoline, into the fuel tank.

Mix thoroughly, then pour the remainder of the gasoline into the tank.

PORTABLE FUEL TANK PLACEMENT IN THE BOAT

Place the fuel tank in the boat so the vent is higher than the fuel level under
normal boat operating conditions.

FUEL AND OIL

eng 29

Remote Control Features

Your boat may be equipped with the Mercury Precision or Quicksilver remote
control shown. If not, consult your dealer for a description of the functions and
operations of the remote control.

a - Remote control handle ‑ Forward (F), Neutral (N), Reverse (R)
b - Throttle only lever
c - Ignition key switch
d - Lanyard stop switch

Tilting Outboard

BASIC TILTING OPERATION

The tilt feature allows the operator to tilt the outboard to a higher tilt angle for
operation in shallow water, or tilt the outboard to the full up position.

When running the outboard, keep the tilt lever in the release position. This
allows the outboard to return to the running position if the outboard should hit
an underwater obstacle and be lifted up.

Moving the tilt lever to the tilt position will allow the outboard to lock into the
shallow water drive position or the full up position.

37982

a

b

c

d

FEATURES AND CONTROLS

30 eng

TILT UP

Turn the reverse lock lever to release side and tilt up the engine; the engine is
set automatically.

a - Reverse lock lever

TILT DOWN

Turn the reverse lock lever to lock side, lift up the engine slightly, and put it
down. Reverse lock is done automatically.

a - Reverse lock lever

Shallow Water Operation

The outboard is equipped with a shallow water tilt feature that allows you to tilt
the outboard to a higher tilt angle to prevent hitting bottom.

IMPORTANT: Before tilting the outboard into the shallow water drive position,
reduce engine speed to idle and shift engine into neutral gear.

37535

a

37537

a

FEATURES AND CONTROLS

eng 31

SHALLOW WATER RUNNING POSITION

Turn the reverse lock lever to release side and tilt up the engine to set the
engine to shallow water running position.

a - Reverse lock lever

TILT DOWN FROM SHALLOW WATER RUNNING POSITION

Turn the reverse lock lever to lock side, lift up the engine slightly, and put it
down. Reverse lock is done automatically.

a - Reverse lock lever

IMPORTANT: While in shallow water drive position, do not operate the
outboard in reverse. Operate the outboard at slow speed and keep the cooling
water intake submerged.

Trim Adjustment

Trim of the motor can be adjusted to suit the transom angle and loading
conditions of your boat. Be sure to maintain the anti‑ventilation plate parallel to
the water level during cruising.

•

Correct trim: Maintain the trim position pin perpendicular to the water
level to keep your boat level during cruising.

•

Trim down: If the bow rises too high, causing unstable cruising, trim the
trim position pin down.

37535

a

37537

a

FEATURES AND CONTROLS

32 eng

•

Trim up: If the bow falls into the water level when cruising, trim the trim
position pin up.

a - Correct trim
b - Trim down
c - Trim up
d - Trim position pin
e - Move pin to raise bow up
f - Move pin to lower bow down

Steering Friction Adjustment

Steering friction can be adjusted according to your preference with the steering
co‑pilot.

!

WARNING

Insufficient friction adjustment can cause serious injury or death due to loss
of boat control. When setting the friction adjustment, maintain sufficient
steering friction to prevent the outboard from steering into a full turn if the
tiller handle or steering wheel is released.

Adjust the steering co‑pilot to achieve desired steering friction.

• Turn clockwise for more friction.

37883

a

b

c

d

e

f

FEATURES AND CONTROLS

eng 33

• Turn counterclockwise for less friction.

a - Steering co‑pilot

Trim Tab Adjustment

Propeller steering torque will cause the boat to pull in one direction. Steering
torque results from the outboard not being tilted so the propeller shaft is parallel
to the water surface. The trim tab can help compensate for this steering torque
in many cases and can be adjusted within limits to reduce any unequal steering
effort.

• Operate the boat at normal cruising speed with the outboard set at the
desired operating angle position. Turn the boat left and right and note the
direction the boat turns more easily.

• If adjustment is necessary, loosen the trim tab bolt and make small
adjustments at a time.

• After adjustment, securely tighten the trim tab bolt.

NOTE: Check for looseness of the bolt and the trim tab at regular intervals. Due
to corrosion, the trim tab will wear down over time.

IMPORTANT: The trim tab also acts as an anode to prevent galvanic corrosion.
Do not apply any paint, grease, or other material to the surface of the trim tab.

NOTE: Trim tab adjustment will have little effect reducing steering torque if the
outboard is installed with the anti‑ventilation plate approximately 50 mm (2 in.)
or more above the boat bottom.

The trim tab is located under the anti‑ventilation plate.

• If the boat steers toward the left, set the trim tab in the direction of B.

37516

a

FEATURES AND CONTROLS

34 eng

• If the boat steers toward the right, set the trim tab in the direction of C.

a - Trim tab
b - Steers toward the left, set the trim tab in the direction of B
c - Steers toward the right, set the trim tab in the direction of C
d - Turning left
e - Turning right

37494

a

b

c

d

e

FEATURES AND CONTROLS

eng 35

Prestarting Check List

• Operator knows safe navigation, boating, and operating procedures.

• An approved personal flotation device of suitable size for each person
aboard and readily accessible (it is the law).

• A ring type life buoy or buoyant cushion designed to be thrown to a
person in the water.

• Know your boats' maximum load capacity. Look at the boat capacity plate.

• Fuel supply OK.

• Arrange passengers and load in the boat so the weight is distributed
evenly and everyone is seated in a proper seat.

• Tell someone where you are going and when you expect to return.

• It is illegal to operate a boat while under the influence of alcohol or drugs.

• Know the waters and area you will be boating; tides, currents, sand bars,
rocks, and other hazards.

•

Make inspection checks listed in Maintenance ‑ Inspection and

Maintenance Schedule.

Operating in Freezing Temperatures

When using your outboard or having your outboard moored in freezing or near
freezing temperatures, keep the outboard tilted down at all times so the
gearcase is submerged. This prevents the trapped water in the gearcase from
freezing and causing possible damage to the water pump and other
components.

If there is a chance of ice forming on the water, the outboard should be
removed and drained completely of water. If ice should form at the water level
inside the outboard driveshaft housing, it will block water flow to the engine
causing possible damage.

Operating in Saltwater or Polluted Water

We recommend that you flush the internal water passages of your outboard
with fresh water after each use in salt or polluted water. This will prevent a
buildup of deposits from clogging the water passages. Refer to Maintenance ‑
Flushing the Cooling System.

If you keep your boat moored in the water, always tilt the outboard so the
gearcase is completely out of water (except in freezing temperatures) when not
in use.

Wash the outboard exterior and flush out the exhaust outlet of the propeller and
gearcase with fresh water after each use. Each month, spray Mercury Precision
or Quicksilver Corrosion Guard on external metal surfaces. Do not spray on
corrosion control anodes as this will reduce the effectiveness of the anodes.

OPERATION

36 eng

Operating at High Elevations

IMPORTANT: To prevent serious damage to the engine caused by a lean fuel
mixture, do not operate your outboard (if the jets were changed for high
elevation) at a lower elevation unless the jets are changed again to correspond
to the new elevation.

Operating your outboard at an elevation higher than 750 m (2500 ft) above sea
level may require a carburetor jet change and/or different pitch propeller.
Consult your dealer. This will reduce the normal performance loss experienced
as a result of reduced oxygen in the air causing an overly rich fuel mixture.

Engine Break‑in Procedure

IMPORTANT: Failure to follow the engine break‑in procedures can result in
poor performance throughout the life of the engine and can cause engine
damage. Always follow break‑in procedures.

Break‑in running time: 10 hours

Time

0 min.~ 10 min.~ 1 hr.~ 2 hrs.~ 10 hrs.~

Method of
break‑in

Trolling or

idling

Throttle

opening

<1/2
about
3,000

RPM

Throttle

opening <3/4

about 4,000

RPM

Throttle
opening 3/4
about 4,000

RPM

Normal
running

Running
conditions

Cruising at

minimum

speed

—

Full‑throttle

run is allowed

for 1 min. in 10

min.

Full‑throttle

run is allowed

for a short

time.

—

ENGINE BREAK-IN FUEL MIXTURE

Use a 25:1 gasoline/oil mixture in the first tank of fuel.
The use of poor quality fuel will shorten the life of a motor and cause trouble,

including starting failure. It is recommended to use a high quality gasoline and
genuine or recommended engine oil. (Refer to Fuel and Oil section.)

OPERATION

eng 37

Starting the Engine

PREPARATIONS

1. Install the fuel connector to the engine side connector.

37522

2. Loosen the air vent screw on the tank cap. For tanks with a fuel tank auto
air vent (optional): There is no need to loosen the air vent screw. An air
vent opens automatically when the connector is attached to the tank.

37518

3. Feed fuel to the carburetor by squeezing the primer valve until firm.

a - To fuel tank
b - To outboard
c - Fuel flow direction

37714

a

c

b

OPERATION

38 eng

NOTICE

Without sufficient cooling water, the engine, the water pump, and other
components will overheat and suffer damage. Provide a sufficient supply of
water to the water inlets during operation.

4. Tiller handle models: Set the shift lever to neutral position.

NOTE: Be sure that the shift is at Neutral (N) when starting the engine. This
model is provided with start in gear protection.

5. Turn the throttle grip until the bar mark on the grip faces the triangle mark
on the steering handle.

6. Pull out the choke knob fully. No choke operation is necessary on warmed
engine.

N

37521

7. Remote control models: Insert the key.

OPERATION

eng 39

8. Turn the key to the on position, and push it for choke operation. No need
to push the key when the engine is warm.

a - Off
b - On
c - Push for choke operation

9. Place the control lever at Neutral (N), and move the throttle only lever to
the open position.

a - Fully opened position
b - Fully closed position
c - Throttle only lever
d - Ignition key switch
e - Lanyard stop switch

37466

a

b

c

37715

N

c

d
e

a

b

OPERATION

40 eng

SET THE LANYARD STOP SWITCH TO RUN POSITION

Be sure to connect the lanyard stop switch to your body. The engine will shut
down if the stop lanyard is disconnected.

Tiller handle models

a - Lanyard stop switch
b - Stop switch lock
c - Hook

Remote control models

a - Hook
b - Off
c - On
d - Lanyard stop switch

NOTE: The engine will not start unless this switch has been properly connected
and locked beforehand. Refer to

General Information ‑ Lanyard Stop Switch

.

37465

a

b

c

37716

a

b

c

d

OPERATION

eng 41

STARTING THE ENGINE

1. Pull the rewind starter slowly until you feel the starter engage, then pull
rapidly to crank the engine. Allow the rope to return slowly.

a - Slowly
b - Rapidly

IMPORTANT: Before starting, read the Prestarting Check List, special
operating instructions, and Engine Break‑in Procedures in the Operation
section.

2. Tiller handle models: Push the starter button.

3. After the engine starts, release the button.

37524

4. Remote control models: Insert, push, and turn the key to the start position.

37523

a

b

OPERATION

42 eng

NOTE: When restarting a warm engine, do not push the key; merely turn it to
the start position.

a - On
b - Start

5. When the engine starts, release the key, and it will return automatically to
the run position.

6. If the engine fails to start in 10 seconds, wait 30 seconds and try again. If
the engine begins to stall, reprime (push key in) until the engine is
running.

IMPORTANT: RAPID ACCELERATION HAZARD: Before shifting your
outboard from neutral into gear, decrease engine speed to slow. This will
prevent a rapid acceleration that can cause people in the boat to be thrown
from their seats or out of the boat, causing injury or death.

STARTING GUIDELINE

Temperature

Starting procedure

Over 25 °C (77 °F)

Turn the throttle grip to the original position. Pull the
choke knob and rewind starter once. Turn the throttle
grip to start position, push the choke knob back, then
pull the rewind starter until the engine starts.

15 °C–25 °C
(59 °F–77 °F)

Turn the throttle grip to start position. Pull the choke
knob and rewind starter once. Push the choke knob
back and pull the rewind starter until the engine starts.

Below 15 °C (59 °F)

Turn the throttle grip to start position. Pull the choke
knob and the rewind starter until combustion occurs.
Push the choke knob back and pull the rewind starter
until the engine starts.

37717

a

b

OPERATION

eng 43

Warm‑Up

Run the engine at a low speed for about three minutes for warm‑up operation
before cruising, permitting the oil to circulate throughout the engine, otherwise
the life of the engine will be shortened greatly. During warm‑up operation,
confirm that cooling water is discharged from its water pump indicator hole.

IMPORTANT: If cooling water is not discharged, and operation continues, it
may cause overheating, resulting in engine damage.

a - Water pump indicator
b - Cooling water discharge port

Gear Shifting

FORWARD

IMPORTANT: Observe the following:

•

Never shift the outboard into or out of gear unless the engine speed
is at idle. Shifting at higher than engine idle speed could cause
damage to the gearcase.

•

Do not shift the outboard into reverse when the forward motion of
the boat is greater than a no wake speed. Shifting into reverse at
higher boat speeds could cause the engine to stall, and in some
situations, this could cause water to be drawn into the cylinders,
resulting in severe engine damage.

•

Do not shift the outboard into reverse when the engine is not
running. Damage to the shift linkage could occur.

• The outboard has three gear shift positions: Forward (F), Neutral (N), and
Reverse (R).

• Remote control models—always stop at the neutral position to allow the
engine idle speed to stabilize before shifting into another gear.

37514

a

b

OPERATION

44 eng

• Tiller handle models—reduce the engine speed to idle before shifting into
another gear.

• Always shift the outboard into gear with a quick motion.

• After shifting the outboard into gear, advance the remote control handle or
rotate the throttle grip (tiller handle) to increase the engine speed.

Tiller handle models: Turn the throttle grip to the slow position and move the
shift lever to Forward (F) position swiftly when the engine speed drops to its
lowest level.

a - Reverse (R)
b - Forward (F)

Remote control models: Move the throttle only lever to the lower position, then
shift the control lever to Forward (F) position.

37713

a

b

OPERATION

eng 45

NOTE: Forward running is not possible unless the throttle only lever is at the
lower position.

a - Fully opened position
b - Fully closed position
c - Throttle range
d - Shift range
e - Neutral (N)
f - Forward (F)
g - Reverse (R)
h - Throttle only lever

REVERSE

Tiller handle models: Move the shift lever to the Reverse (R) position swiftly
when the engine speed drops to its lowest level.

NOTE: Confirm that the reverse lock lever is at the lock position.

a - Reverse lock lever: R =

Release, L = Lock

37531

a

b

c

d

e

f

g

a

b

c

d

h

37538

a

OPERATION

46 eng

Remote control models: Shift the outboard only when the engine is at idle
speed. To change Forward (F) to Reverse (R), first idle the engine and shift into
Neutral (N). With the engine still running, slowly engage and gradually increase
the reverse speed.

NOTE: Confirm that the reverse lock lever is at the lock position.

a - Reverse lock lever: R =

Release, L = Lock

Stopping the Engine

1. Tiller handle models: Reduce the speed to trolling speed by turning the
throttle grip to the slow position.

2. Place the shift lever at Neutral (N).

3. Press the stop switch until the engine stops completely, or pull the lanyard
stop switch.

37877

37538

a

OPERATION

eng 47

4. Remote control models: Place the remote control lever at Neutral (N) and
idle the engine.

37882

N

5. Turn the key to the off position, or pull the lanyard stop switch.

a - Hook
b - Off
c - On
d - Lanyard stop switch

IMPORTANT: Follow the instructions below.

•

After the engine stops, tighten the air vent screw on the tank cap.

•

Disconnect the fuel connector from the engine.

•

For electric start models, disconnect the cables from the battery
when not in use for extended periods.

Emergency Starting

If the starter system fails, use the spare starter rope (provided) and follow
procedure.

1. Ensure the lanyard stop switch is in run position.

37716

a

b

c

d

OPERATION

48 eng

2. Remove the starter rope.

3. Wind a pull rope around the flywheel.

4. Use a 10 mm socket wrench as a pull grip, as shown below.

37880

5. Remote control models: Ensure the key switch is in the on position.

NOTE: Confirm that the shift lever is in Neutral (N).

!

WARNING

The exposed moving flywheel can cause serious injury. Keep your hands,
hair, clothing, tools, and other objects away from engine when starting or
running the engine. Do not attempt to reinstall the rewind starter assembly or
top cowl when engine is running.

OPERATION

eng 49

Cleaning Care Recommendations

OUTBOARD CARE

To keep your outboard in the best operating condition, it is important that your
outboard receive the periodic inspections and maintenance listed in the
Inspection and Maintenance Schedule. We urge you to keep it maintained
properly to ensure the safety of you and your passengers, and retain its
dependability.

Record maintenance performed in the Maintenance Log at the back of this
book. Save all maintenance work orders and receipts.

Selecting Replacement Parts For Your Outboard

We recommend using original Mercury Precision or Quicksilver replacement
parts and Genuine Lubricants.

DO NOT USE CAUSTIC CLEANING CHEMICALS

IMPORTANT: Do not use caustic cleaning chemicals on the outboard power
package. Some cleaning products contain strong caustic agents such as hull
cleaners with hydrochloric acid. These cleaners can degrade some of the
components they come in contact with including critical steering fasteners.

Damage to steering fasteners may not be obvious during visual inspection and
this damage may lead to catastrophic failure. Some caustic cleaning chemicals
may cause or accelerate corrosion. Exercise caution when using cleaning
chemicals around the engine and follow the recommendations on the
packaging of the cleaning product.

CLEANING GAUGES

IMPORTANT: Never use high‑pressure water to clean gauges.
Routine cleaning of the gauges is recommended to prevent a buildup of salt

and other environmental debris. Crystalized salt can scratch the gauge display
lens when using a dry or damp cloth. Ensure that the cloth has a sufficient
amount of fresh water to dissolve and remove salt or mineral deposits. Do not
apply aggressive pressure on the display lens while cleaning.

When water marks cannot be removed with a damp cloth, mix a 50/50 solution
of warm water and isopropyl alcohol to clean the display lens. Do not use
acetone, mineral spirits, turpentine type solvents, or ammonia based cleaning
products. The use of strong solvents or detergents may damage the coating,
the plastics, or the rubber keys on the gauges. If the gauge has a sun cover
available, it is recommended that the cover be installed when the unit is not in
use to prevent UV damage to the plastic bezels and rubber keys.

CLEANING REMOTE CONTROLS

IMPORTANT: Never use high‑pressure water to clean remote controls.

MAINTENANCE

50 eng

Routine cleaning of the remote control external surfaces is recommended to
prevent a buildup of salt and other environmental debris. Use a cloth towel
which has a sufficient amount of fresh water to dissolve and remove salt or
mineral deposits.

When water marks cannot be removed with a damp cloth, mix a 50/50 solution
of warm water and isopropyl alcohol to clean the remote control. Do not use
acetone, mineral spirits, turpentine type solvents, or ammonia based cleaning
products. The use of strong solvents or detergents may damage the coating,
the plastics, or the rubber components on the remote control.

CLEANING CARE FOR TOP AND BOTTOM COWLS

IMPORTANT: Dry wiping (wiping the plastic surface when it is dry) will result in
minor surface scratches. Always wet the surface before cleaning. Do not use
detergents containing hydrochloric acid. Follow the cleaning and waxing
procedure.

Cleaning and Waxing Procedure

1. Before washing, rinse the cowls with clean water to remove dirt and dust
that may scratch the surface.

2. Wash the cowls with clean water and a mild nonabrasive soap. Use a soft
clean cloth when washing.

3. Dry thoroughly with a soft clean cloth.

4. Wax the surface using a nonabrasive automotive polish (polish designed
for clear coat finishes). Remove the applied wax by hand using a clean
soft cloth.

5. To remove minor scratches, use Mercury Marine Cowl Finishing
Compound (92‑859026K 1).

Inspection and Maintenance Schedule

DAILY CHECKS

• Check the engine oil level

• Check the lanyard stop switch

• Inspect the fuel system for leaks

• Inspect the engine tightness on the transom

• Check the steering system for binding

• Check the propeller for damage

• Inspect the hydraulic steering fittings and hoses for leaks or signs of
damage, if equipped

• Check the hydraulic steering fluid level, if equipped

AFTER EACH USE

• Wash the power package exterior with fresh water

• Flush the outboard cooling system, saltwater or brackish water only

MAINTENANCE

eng 51

ANNUALLY OR 100 HOURS

• Grease the engine, if applicable

• Change the engine oil and filter, if equipped

• Inspect the thermostat, saltwater or brackish water only

• Add Quickleen to the fuel tank, once per year, per engine

• Apply antiseize to the spark plug threads

• Replace the gear lubricant

• Inspect the corrosion control anodes

• Lubricate the propeller shaft splines

• Replace all filters on the suction side of the fuel system—dealer item

• Lubricate the driveshaft splines—dealer item

• Check the tightness on all the fasteners—dealer item

• Check the torque of the outboard mounting hardware—dealer item

• Check the battery condition and tightness of the battery cable connection,
if equipped—dealer item

THREE YEARS OR 300 HOURS

• Replace the spark plugs

• Replace the water pump impeller—dealer item

• Inspect the carbon fiber reeds, if equipped—dealer item

• Inspect the wire harness connectors—dealer item

• Check the remote control cable adjustment, if equipped—dealer item

• Replace the high‑pressure fuel filter, if equipped—dealer item

• Replace the accessory drive belt, if equipped—dealer item

• Check the power trim fluid level, if equipped—dealer item

• Inspect the engine motor mounts—dealer item

Flushing the Cooling System

Flush the internal water passages of the outboard with fresh water after each
use in salt, polluted, or muddy water. This will help prevent a buildup of
deposits from clogging the internal water passages.

Use a Mercury Precision or Quicksilver accessory (or equivalent) flushing
attachment.

IMPORTANT: The engine must be run during flushing in order to open the
thermostat and circulate water through the water passages.

MAINTENANCE

52 eng

!

WARNING

Rotating propellers can cause serious injury or death. Never operate the boat
out of the water with a propeller installed. Before installing or removing a
propeller, place the drive unit in neutral and engage the lanyard stop switch
to prevent the engine from starting. Place a block of wood between the
propeller blade and the anti‑ventilation plate.

1.

Remove the propeller. Refer to Propeller Replacement. Install the
flushing attachment so the rubber cups fit tightly over the cooling water
intake.

27256

Flushing Device 91‑44357Q 2

9192

Attaches to the water intakes; provides
a fresh water connection when flushing
the cooling system or operating the
engine.

2. Attach a water hose to the flushing attachment. Turn on the water and
adjust the flow so water is leaking around the rubber cups to ensure the
engine receives an adequate supply of cooling water.

27259

3. Start the engine and run it at idle speed in neutral shift position.

IMPORTANT: Do not run the engine above idle when flushing.

MAINTENANCE

eng 53

4. Adjust the water flow (if necessary) so excess water continues leaking out
from around the rubber cups to ensure the engine is receiving an
adequate supply of cooling water.

27260

5. Check for a steady stream of water flowing out of the water pump
indicator hole. Continue flushing the outboard for 3 to 5 minutes, carefully
monitoring water supply at all times.

6. Stop the engine, turn off the water, and remove the flushing attachment.
Install the propeller.

Top Cowl Removal and Installation

REMOVAL

1. Unlock the rear latch by pushing lever down.

29054

2. Lift rear of cowl and disengage front hook.

26851

INSTALLATION

1. Engage the front hook and push cowl back over the cowl seal.

MAINTENANCE

54 eng

2. Push cowl down and move the rear latch lever up to lock.

Battery Inspection

The battery should be inspected at periodic intervals to ensure proper engine
starting capability.

IMPORTANT: Read the safety and maintenance instructions which accompany
your battery.

1. Turn off the engine before servicing the battery.

2. Ensure the battery is secure against movement.

3. Battery cable terminals should be clean, tight, and correctly installed.
Positive to positive and negative to negative.

4. Ensure the battery is equipped with a nonconductive shield to prevent
accidental shorting of battery terminals.

Fuel System

!

WARNING

Fuel is flammable and explosive. Ensure that the key switch is off and the
lanyard is positioned so that the engine cannot start. Do not smoke or allow
sources of spark or open flame in the area while servicing. Keep the work
area well ventilated and avoid prolonged exposure to vapors. Always check
for leaks before attempting to start the engine, and wipe up any spilled fuel
immediately.

Before servicing any part of the fuel system, stop the engine and disconnect
the battery. Drain the fuel system completely. Use an approved container to
collect and store fuel. Wipe up any spillage immediately. Material used to
contain spillage must be disposed of in an approved receptacle. Any fuel
system service must be performed in a well‑ventilated area. Inspect any
completed service work for sign of fuel leakage.

FUEL LINE INSPECTION

Visually inspect the fuel line and primer bulb for cracks, swelling, leaks,
hardness, or other signs of deterioration or damage. If any of these conditions
are found, the fuel line or primer bulb must be replaced.

ENGINE FUEL FILTER

Inspect the sight bowl for water accumulation and inspect the filter element for
sediment. Clean the tank and filters as follows.

CLEANING FUEL TANK

1. Water or dirt in the fuel tank may cause engine trouble.

2. Clean the tank at specified times or after long storage period (over three
months).

Fuel filters are provided inside the fuel tank and at the engine.

MAINTENANCE

eng 55

1. Unscrew four screws, remove the housing, then clean the fuel filter.

a - Filter: Unscrew the fuel pickup elbow and then clean it
b - Fuel pickup elbow

2. Remove the fuel filter bowl, then clean the fuel filter at the engine.

a - Carburetor
b - Fuel filter bowl

Fuse Replacement ‑ Electric Start Remote Control Models

IMPORTANT: Always carry spare SFE 20 amp fuses.
The electric starting circuit is protected from overload by an SFE 20 amp fuse.

If the fuse is blown, the electric starter motor will not operate. Try to locate and
correct the cause of the overload. If the cause is not found, the fuse may blow
again. Replace fuse with a fuse of the same rating.

Corrosion Control Anode

Your outboard has a corrosion control anode installed on the gearcase and in
the cylinder. An anode helps protect the outboard against galvanic corrosion by
sacrificing its metal to be slowly corroded instead of the outboard metals.

37711

b

a

37710

b

a

MAINTENANCE

56 eng

The anode requires periodic inspection, especially in saltwater which will
accelerate the erosion. To maintain this corrosion protection, always replace
the anode before it is completely eroded. Never paint or apply a protective
coating on the anode, as this will reduce effectiveness of the anode.

a - Anode (trim tab)

Important:

•

Before replacing the anode, remove the spark plug cap to make sure
the engine will not start, then check and replace the anode.

•

If the anode is worn out or no anode is fitted on the outboard motor,
aluminum parts will corrode more rapidly which can cause paint to
peel off and damage the surface.

Propeller Replacement

!

WARNING

Rotating propellers can cause serious injury or death. Never operate the boat
out of the water with a propeller installed. Before installing or removing a
propeller, place the drive unit in neutral and engage the lanyard stop switch
to prevent the engine from starting. Place a block of wood between the
propeller blade and the anti‑ventilation plate.

1. Shift outboard to Neutral (N) position.

38347

37879

a

MAINTENANCE

eng 57

2. Remove the spark plug leads to prevent the engine from starting.

26899

3. Place a block of wood between the gearcase and the propeller to hold the
propeller and remove the propeller nut.

27296

4. Remove the propeller from the shaft. If the propeller is seized to the shaft
and cannot be removed, have the propeller removed by an authorized
dealer.

a - Cotter pin
b - Nut
c - Washer
d - Propeller
e - Thrust hub

38055

a

c

d

e

b

MAINTENANCE

58 eng

5. Coat the propeller shaft with Mercury Extreme Grease or 2‑4‑C with
PTFE.

27305

Tube Ref

No.

Description Where Used Part No.

Extreme Grease Propeller shaft 8M0071842

95

2-4-C with PTFE Propeller shaft 92-802859A 1

IMPORTANT: To prevent the propeller hub from corroding and seizing to the
propeller shaft (especially in saltwater), always apply a coat of the
recommended lubricant to the entire propeller shaft at the recommended
maintenance intervals, and also each time the propeller is removed.

MAINTENANCE

eng 59

6. Install forward thrust hub, propeller, washer, nut, and cotter pin onto the
propeller shaft.

a - Cotter pin
b - Nut
c - Washer
d - Propeller
e - Forward thrust hub
f - Propeller shaft

7. Place a block of wood between the gearcase and propeller and tighten
the propeller nut.

27341

8. Install the spark plug leads.

37520

a

b

c

d

e

f

MAINTENANCE

60 eng

Spark Plug Inspection and Replacement

!

WARNING

Damaged spark plug boots may emit sparks that can ignite fuel vapors under
the engine cowl, resulting in serious injury or death from a fire or explosion.
To avoid damaging the spark plug boots, do not use any sharp object or
metal tool to remove the spark plug boots.

1. Remove the spark plug boots. Twist the rubber boots slightly and pull off.

26899

2. Remove the spark plugs to inspect. Replace spark plug if electrode is
worn or the insulator is rough, cracked, broken, blistered, or fouled.

26946

3. Set the spark plug gap to specification.

26947

Spark Plug
Spark plug gap 1.0 mm (0.035 in.)

4. Before installing spark plugs, clean off any dirt on the spark plug seats.
Install plugs finger‑tight, and then tighten 1/4 turn or torque to
specifications.

Description

Nm lb‑in. lb‑ft

Spark plug 27 – 20

MAINTENANCE

eng 61

Lubrication Points

It is important to inspect and maintain your outboard motor regularly.
Maintenance intervals should be determined according to the number of hours
or number of months, whichever comes first. For periodic servicing and
maintenance guidelines, please contact your local Mercury dealer.

Item

Every 50 hours or 3

months

Every 100 hours or

6 months

Action

Sliding and
rotating parts

Yes Yes

Apply and pump

in grease

Grease
fittings

Yes Yes

Apply and pump

in grease

Gearcase Lubricant

GEARCASE LUBRICATION

When adding or changing gearcase lubricant, visually check for the presence of
water in the lubricant. If water is present, it may have settled to the bottom and
will drain out prior to the lubricant, or it may be mixed with the lubricant, giving it
a milky colored appearance. If water is noticed, have the gearcase checked by
your dealer. Water in the lubricant may result in premature bearing failure or, in
freezing temperatures, will turn to ice and damage the gearcase.

Remove the fill/drain plug and examine the magnetic end for metal particles. A
small amount of metal filings or fine metal particles indicates normal gear wear.
An excessive amount of metal filings or larger particles (chips) may indicate
abnormal gear wear and should be checked by an authorized dealer.

CHANGING GEAR OIL

1. Place the outboard in a vertical operating position.

2. Place a drain pan below the outboard.

MAINTENANCE

62 eng

3. Remove the oil plugs (upper and lower) and drain the gear oil completely.

37849

4. Place the lubricant tube into the fill/drain hole and add the lubricant until it
appears at the upper oil plug hole.

a - Upper oil plug hole

5. Install the upper oil plug before removing the lubricant tube.

37848

a

MAINTENANCE

eng 63

6. Remove the lubricant tube and install the lower oil plug.

37849

GEARCASE LUBRICANT CAPACITY

Gearcase lubricant capacity is approximately 280 cc (9.5 fl oz).

GEARCASE LUBRICANT RECOMMENDATION

Mercury or Quicksilver Premium or High Performance Gear Lubricant.

Submerged Outboard

A submerged outboard will require service within a few hours by an authorized
dealer once the outboard is recovered from the water. This immediate attention
by a servicing dealer is necessary once the engine is exposed to the
atmosphere to minimize internal corrosion damage to the engine.

Following are the emergency measures to be taken on the submerged
outboard.

1. Immediately take it out of the water and wash it with fresh water to
remove salt or dirt.

2. Remove the spark plugs and completely drain the water from the engine
by pulling the rewind starter several times.

3. Sufficiently inject genuine engine oil through the spark plug hole and into
the crankcase from the carburetor side. Pull the rewind starter several
times to circulate the oil throughout the motor.

MAINTENANCE

64 eng

Storage Preparation

The major consideration in preparing your outboard for storage is to protect it
from rust, corrosion, and damage caused by freezing of trapped water.

The following storage procedures should be followed to prepare your outboard
for out of season storage or prolonged storage (two months or longer).

NOTICE

Without sufficient cooling water, the engine, the water pump, and other
components will overheat and suffer damage. Provide a sufficient supply of
water to the water inlets during operation.

FUEL SYSTEM

IMPORTANT: Gasoline containing alcohol (ethanol or methanol) can cause a
formation of acid during storage and can damage the fuel system. If the
gasoline being used contains alcohol, it is advisable to drain as much of the
remaining gasoline as possible from the fuel tank, remote fuel line, and engine
fuel system.

Fill the fuel tank and engine fuel system with treated (stabilized) fuel to help
prevent formation of varnish and gum. Proceed with the following instructions.

• Portable fuel tank ‑ Pour the required amount of gasoline stabilizer (follow
instructions on container) into the fuel tank. Tip fuel tank back and forth to
mix stabilizer with the fuel.

• Permanently installed fuel tank ‑ Pour the required amount of gasoline
stabilizer (follow instructions on container) into a separate container and
mix with approximately 1 liter (1 U.S. qt) of gasoline. Pour this mixture into
the fuel tank.

• Place the outboard in water or connect flushing attachment for circulating
cooling water. Run the engine at idle RPM for ten minutes to fill the
engine fuel system with stabilized fuel.

Protecting External Outboard Components

•

Lubricate all outboard components listed in Maintenance ‑ Inspection
and Maintenance Schedule.

• Touch up any paint nicks. See your dealer for touch‑up paint.

• Spray Quicksilver or Mercury Precision Lubricants Corrosion Guard on
external metal surfaces (except corrosion control anodes).

Tube Ref

No.

Description Where Used Part No.

120

Corrosion Guard External metal surfaces 92-802878 55

STORAGE

eng 65

Protecting Internal Engine Components

NOTE: Make sure the fuel system has been prepared for storage. Refer to

Fuel

System

, preceding.

IMPORTANT: Refer to Maintenance ‑ Spark Plug Inspection and Replacement
for correct procedure for removing spark plug boots.

• Place the outboard in water or connect flushing attachment for circulating
cooling water. Start the engine and let it run in neutral to warm up.

• With engine running at fast idle, stop the fuel flow by disconnecting the
remote fuel line. When engine begins to stall, quickly spray Quicksilver or
Mercury Precision Lubricants Storage Seal into carburetor until engine
stops from lack of fuel.

• Remove the spark plugs and inject a five second spray of storage seal
around the inside of the cylinder.

• Rotate the flywheel manually several times to distribute the storage seal
in the cylinder. Install the spark plug.

Gearcase

•

Drain and refill the gearcase lubricant (refer to Gearcase Lubricant).

Positioning Outboard for Storage

Store outboard in an upright (vertical) position to allow water to drain out of the
outboard.

NOTICE

Storing the outboard in a tilted position can damage the outboard. Water
trapped in the cooling passages or rain water collected in the propeller
exhaust outlet in the gearcase can freeze. Store the outboard in the full down
position.

Battery Storage

• Follow the battery manufacturer's instructions for storage and charging.

• Remove the battery from the boat and check water level. Charge if
necessary.

• Store the battery in a cool, dry place.

• Periodically check the water level and charge the battery during storage.

STORAGE

66 eng

Starter Motor Will Not Crank the Engine (Electric Start Models)

POSSIBLE CAUSES

• Remote control models ‑ Blown 20 amp fuse in the starting circuit. Refer
to Maintenance section.

• Outboard is not shifted to neutral position.

• Weak battery or battery connections are loose or corroded.

• Ignition key switch failure.

• Wiring or electrical connection faulty.

• Starter motor or starter solenoid failure.

Engine Will Not Start

POSSIBLE CAUSES

• Lanyard stop switch not in "RUN" position.

•

Incorrect starting procedure. Refer to Operation section.

• Old or contaminated gasoline.

•

Engine flooded. Refer to Operation section.

• Fuel is not reaching the engine.

a. Fuel tank is empty.
b. Fuel tank vent not open or restricted.
c. Fuel line is disconnected or kinked.
d. Primer bulb not squeezed.
e. Primer bulb check valve is faulty.
f.

Fuel filter is obstructed. Refer to Maintenance section.
g. Fuel pump failure.
h. Fuel tank filter obstructed.

• Ignition system component failure.

•

Spark plugs fouled or defective. Refer to Maintenance section.

Engine Runs Erratically

POSSIBLE CAUSES

•

Spark plugs fouled or defective. Refer to Maintenance section.

• Incorrect setup and adjustments.

• Fuel is being restricted to the engine.

•

Engine fuel filter is obstructed. Refer to Maintenance section.

• Fuel tank filter obstructed.

• Stuck anti‑siphon valve on built in fuel tank.

• Fuel line is kinked or pinched.

• Fuel pump failure.

TROUBLESHOOTING

eng 67

• Ignition system component failure.

Performance Loss

POSSIBLE CAUSES

• Throttle not fully open.

• Damaged or improper size propeller.

• Incorrect engine timing, adjustments, or setup.

• Boat overloaded or load improperly distributed.

• Excessive water in bilge.

• Boat bottom is dirty or damaged.

Battery Will Not Hold Charge

POSSIBLE CAUSES

• Battery connections are loose or corroded.

• Low electrolyte level in battery.

• Worn out or inefficient battery.

• Excessive use of electrical accessories.

• Defective rectifier, alternator, or voltage regulator.

TROUBLESHOOTING

68 eng

Mercury Marine Validated Engine Mounting Hardware

IMPORTANT: Mercury Marine provides validated fasteners and installation
instructions, including torque specifications, with all of our outboards so they
can be properly secured to boat transoms. Improper installation of the outboard
can cause performance and reliability issues that can lead to safety concerns.
Follow all of the instructions relating to the outboard installation. DO NOT
mount any other accessory onto the boat with the fasteners provided with the
outboard. For example, do not mount tow sport bars or boarding ladders onto
the boat using the mounting hardware included with the outboard. Installing
other products onto the boat that utilize the outboard mounting hardware will
compromise the ability of that hardware to properly and safely secure the
outboard to the transom.

Outboards that require validated mounting hardware will have the following
decal on the transom clamp.

51965

Installing Outboard

We strongly recommend that your dealer install your outboard and related
accessories to ensure proper installation and good performance. If you install
the outboard yourself, follow the instructions in the manual which is provided
with the outboard.

NOTE: Most boats are rated and certified in terms of their maximum
horsepower limit, and this is shown on the boat's certification plate. Do not
equip your boat with an outboard that exceeds this limit. If in doubt, contact
your dealer. Do not operate the engine until it has been securely mounted on
the boat in accordance with the instructions below.

ENGINE INSTALLATION

eng 69

1. One outboard: Position the outboard motor at the center of the stern.
Refer to General Information ‑ 25/30 Specifications for the transom
height.

a - Transom height

2. Two outboards: Position the outboard engines about 580 mm (23 in.)
apart. Refer to General Information ‑ 25/30 Specifications for the
transom height.

a - Transom height

3. Clearance between the anti‑ventilation plate of the motor and the bottom
of the boat must be 30–50 mm (1.2–2 in.). If the height difference exceeds
30–50 mm (1.2–2 in.), engine power performance is likely to be reduced
as a result of increased water resistance to the gearcase assembly.

37508

a

580 mm

37509

a

a

ENGINE INSTALLATION

70 eng

NOTE: Select an outboard motor that allows the clearance shown below.

a - Bottom of boat
b - Anti‑ventilation plate

4. After positioning the clamp brackets, attach it with the clamp screws then
drill two holes in the transom board, matching the holes in the clamp
bracket. Secure the engine with the supplied bolts and nuts. Be sure to
use the washers.

a - Trim position pin

holes

b - Bolt
c - Clamp screw
d - Nut

TRANSOM MATCHING

NOTE: Be sure that the anti‑ventilation plate of the outboard is below the water
surface when running at wide‑open throttle. In case the above condition cannot
be met due to a bottom shape of your boat, please consult the dealer.

30–50 mm (1.2” 2”)–

37510

a

b

37511

a

b

c

d

ENGINE INSTALLATION

eng 71

Installing the Remote Control Device

RIGHT-HAND STEERING

1. Position the remote control box in a place that will not obstruct handling of
the control levers and switches. Confirm there is no obstacle in the
passage of the remote control cables.

37529

2. Remote control features:

a - Fully opened position
b - Fully closed position
c - Throttle range
d - Shift range
e - Neutral (N)
f - Forward (F)
g - Reverse (R)
h - Throttle only lever

37531

a

b

c

d

e

f

g

a

b

c

d

h

ENGINE INSTALLATION

72 eng

3. Determining remote control cable length: A guideline for determining the
proper length for a remote control cable is dimensions A plus B plus 300
mm (1 foot).

a - Center of transom

NOTE: The minimum bend radius for a remote control cable is typically 203
mm (8 in.). Avoid making sharp bends.

4. Connecting remote control cables to the remote control box: Remove the
back panel by loosening two screws.

a - Back panel

37530

a

A

B

37528

a

ENGINE INSTALLATION

eng 73

5. Thread the remote control cables through the terminal eyes at a distance
of more than 16 mm (0.63 in.). Securely lock the terminal eyes with the
locknut.

a - Terminal eyes
b - Locknut

6. Press the neck of the shift remote control cable down into the clamp on
the housing of the remote control box. Connect the terminal eye to the
shift arm with the pin and E‑ring. Insert a grommet, supplied with the
remote control box, into the clamp.

a - Grommet
b - Shift arm pin
c - E‑ring
d - Shift arm

11 mm

a

b

37497

37527

a

b

c

d

ENGINE INSTALLATION

74 eng

7. Connect the throttle remote control cable to the throttle arm in a manner
similar to the shift remote control cable.

a - Throttle cable
b - Shift cable
c - Throttle arm
d - Shift arm

8. Install the back panel.

a - Back panel

37526

a

b

c

d

37528

a

ENGINE INSTALLATION

eng 75

9. Install the remote control box with three screws, spacers, and nuts.

a - Screw
b - Remote control box
c - Hull
d - Spacer
e - Washer
f - Nut

37464

a

b

c

d

e

f

ENGINE INSTALLATION

76 eng

10. Connect the remote control cables to the engine and attach the cord
assembly as shown below.

a - Steering hook plate
b - Spacer
c - Clip
d - Neck of remote control cable
e - Shift remote control cable
f - Washer
g - Sleeve guide B: Connect remote control cable to shift lever
h - Shift lever
i - Advance arm
j - Ball joint
k - Holder cap: Connect remote control cable to ball joint
l - Remove grommet from lower motor cover
m - Throttle remote control cable
n - Neck of remote control cable
o - Spacer
p - Clip
q - Stop switch harness

11. Attach a holder cap and a sleeve guide B.

37495

a

c

d

e

f

g

b

h i

j

k

l

m

n

o

p

q

ENGINE INSTALLATION

eng 77

12. Throttle side: Slide a grommet onto an end of the cable, put a holder cap
on it, and lock it with a nut, as shown.

a - Throttle cable
b - Nut
c - Holder cap

13. Shift side: Attach the sleeve guide B to the shift remote control cable, and
lock it with a nut.

a - Neck of remote control cable
b - Shift cable
c - Nut
d - Sleeve guide B

14. Connect the remote control cable to the engine.

15. Throttle side: Insert the throttle cable into a hole of the advancer arm at
the lower cowl, attach the ball joint to the holder cap at the tip of the
remote control cable, and fasten the remote control cable with a clip.
Attach a grommet to the lower cowl.

NOTE: Place the control lever in Neutral (N), and the idling lever in the fully
closed position.

16. Shift side: Insert the lock pin at the sleeve guide B into the shift lever
attaching hole and turn it 90° to lock it, then fasten the remote control
cable with a clip.

37502

a

b

c

37503

a

b

c

d

ENGINE INSTALLATION

78 eng

17. Attach the cord assembly: Connect the cord assembly from the remote
control box to respective terminals through the lower cowl as illustrated.
Fasten the cord assembly with clamps.

a - Cord assembly
b - Black terminal
c - Brown terminal
d - Green terminal
e - Red terminal
f - Rectifier
g - Terminal holder
h - Fuse
i - Clamps
j - Blue terminal
k - Starter solenoid
l - CD unit
m - Choke solenoid

37505

a

b

c

b

c

d

f

j

i

h

j

i

g

k

l

m

n

o

r

s

p

q

e

d

ENGINE INSTALLATION

eng 79

n - Starter solenoid bracket
o - Lower cowl
p - Grommet
q - To remote control box
r - Clamp
s - Screw

ENGINE INSTALLATION

80 eng

18. Connect the cables to their respective terminals at the cable terminal
holder.

a - Magnet lead wire
b - Magnet lead wire
c - Cord assembly
d - Fuse wire
e - CD unit
f - Cord assembly
g - CD unit
h - Starter solenoid
i - Rectifier lead wire
j - Stop switch
k - Choke solenoid
l - Stop switch
m - Cord assembly

YEL

WHT

RED

BRN

BLU

BLK

GRN

YEL

WHT

RED

BRN

BLU

BLK

GRN

RED

37500

a

b

c

d

e

f

g

h

i

j

k l

m

i

ENGINE INSTALLATION

eng 81

WIRE COLOR CODE ABBREVIATIONS

Wire Color Abbreviations

BLK Black

BLU Blue
BRN Brown GRY Gray
GRN Green ORN or ORG Orange
PNK Pink PPL or PUR Purple
RED Red TAN Tan
WHT White YEL Yellow
LT or LIT Light DK or DRK Dark

Attaching the Steering Link Rod

!

WARNING

Improper fasteners or improper installation procedures can result in
loosening or disengagement of the steering link rod. This can cause a
sudden, unexpected loss of boat control, resulting in serious injury or death
due to occupants being thrown within or out of the boat. Always use required
components and follow instructions and torque procedures.

ENGINE INSTALLATION

82 eng

The steering link rod parts are available and assembled as illustrated below.
Spacers may or may not be required depending on cable brands.

a - Grease
b - Spacer (optional)
c - Bolt
d - Washer B
e - Rubber cushion
f - Spring
g - Spacer
h - Collar
i - Locknut
j - Rod
k - Washer A
l - Seal ring

Battery Installation

MOUNTING BATTERY

Follow the battery manufacturer's instructions carefully. Mount battery securely
to the hull in a place free from splashing water.

NOTE: Electric starting outboards must have the battery cables connected to a
battery whenever the engine is running, even if started manually, as damage to
the charging system could result.

a

b

c

d
e

f

a

d

g

h

d

i

j

k

l

d

i

37507

ENGINE INSTALLATION

eng 83

BATTERY CONNECTIONS

Connect a red cable to the positive (+) terminal first and a black cable to the
negative (–) terminal of the battery. Put a red cap on the positive terminal.
When disconnecting battery cables, be sure to disconnect the black cable first,
and then the red cable.

Required battery rating: 12 V battery with a recommended capacity of 70 AH or
over.

• Battery cables must be long enough to allow free steering.

• Battery cables must be arranged and protected from damage during
steering.

• With poor cable connections, the starter will fail to start.

• Battery cable terminals should be clean, tight, and correctly installed.
Positive to positive and negative to negative.

• Battery must be fully charged before running the motor.

a - Red cable
b - Black cable

IMPORTANT: Please follow the instructions below:

• Hydrogen gas is generated when charging a battery. Keep the battery in a
well‑ventilated area during charging. Remove the battery from the boat;
this will protect your hull and interior from damage. Electric sparks,
cigarette smoking, and other sources of fire must be avoided in the
charging area to prevent explosion of the battery.

• The battery fluid (electrolyte) contains sulfuric acid. If electrolyte is spilled
on the skin or clothes, wash with plenty of water and consult a medical
doctor. Always use safety glasses and rubber gloves when handling the
battery.

Propeller Selection

For best all around performance from your outboard/boat combination, select a
propeller that allows the engine to operate in the upper half of the
recommended full throttle RPM range with the boat normally loaded (refer to
General Information ‑ Specifications). This RPM range allows for better
acceleration while maintaining maximum boat speed.

The propeller supplied with your outboard provides the best overall
performance under average operating conditions.

37712

a

b

ENGINE INSTALLATION

84 eng

Alternative propellers are available for specific boating requirements. See your
outboard dealer.

AVAILABLE PROPELLERS

Light‑duty boat — Heavy‑duty boat

Mark 14 (E) 13 (D) 11 (C) 10 (B) 9 (A) 8 (F)

Dimensions
(blade x
diameter x pitch)
mm

3 x 252

x 360

3 x 252

x 332

3 x 250

x 288

3 x 250

x 260

3 x 249

x 236

3 x 260

x 210

If changing conditions cause the RPM to drop below the recommended range,
such as warmer, more humid weather, operation at higher elevations,
increased boat load, or a dirty boat bottom/gearcase, a propeller change or
cleaning may be required to maintain performance and ensure the outboard's
durability.

Check full‑throttle RPM, using an accurate tachometer, with the engine trimmed
out to a balanced‑steering condition (steering effort equal in both directions)
without causing the propeller to break loose.

ENGINE INSTALLATION

eng 85

Associated Parts

Name Quantity Dimensions

Service tools

Tool bag 1
Pliers 1
Socket wrench 1 10 x 13 mm
Socket wrench 1 21 mm
Socket wrench handle 1
Screwdriver 1

Spare parts

Starter rope 1 1000 mm

Spark plug 1

NGK B7HS‑10 or
Champion L82C (Gap:

1.0 mm ‑ 0.035 in.)

Cotter pin 1

Other*

Fuel tank 1
Primer bulb 1 set
Remote control box 1 set
Remote control attachment 1 set
Steering link 1 set
Flushing plug 1

* Not included as standard accessories in some markets.

ASSOCIATED PARTS

86 eng

Accessories

OPTIONAL ACCESSORIES

a - Speedometer (50 MPH)
b - Speedometer (75 MPH)
c - Fuel meter
d - Tachometer
e - Hour meter
f - Genuine engine oil
g - Genuine grease (50 g, 250 g)
h - Genuine gear oil (260 cc, 500 cc)

37846

a

c

b

d

e

f

g

h i

j

k

l

ACCESSORIES

eng 87

i - Touch‑up spray paint (300 ml)
j - Stop switch
k - Extension cord, light
l - Meter lamp switch

a - Turnbuckle plate
b - Twin remote control turnbuckle assembly

37540

a

b

ACCESSORIES

88 eng

a - Steering spacer
b - Steering link assembly (standard: EP type)

37506

a

b

ACCESSORIES

eng 89

a - Twin remote control box kit
b - 3 screws (included in kit)
c - 3 spacers (included in kit)
d - 6 spacers
e - Hull
f - 6 washers
g - 3 nuts

37493

a

b

c

d

e

f

g

ACCESSORIES

90 eng