Mercury 2.5 TwoStroke User manual

Operation
Maintenance
and
Installation
Manual
© 2017 Mercury Marine 2.5, 3.3 TwoStroke
8M0133461 617 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.
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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, 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)
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eng iv

General Information
Boater's Responsibilities..................................................................................... 1
Before Operating Your Outboard........................................................................ 1
Boat Horsepower Capacity................................................................................. 1
Lanyard Stop Switch........................................................................................... 2
Protecting People in the Water........................................................................... 5
Exhaust Emissions............................................................................................. 5
Selecting Accessories for Your Outboard........................................................... 7
Safe Boating Recommendations........................................................................ 7
Recording Serial Number................................................................................. 10
Model Year Production Code............................................................................11
Specifications....................................................................................................11
Installation
Installing Outboard............................................................................................13
Transporting
Carrying Outboard............................................................................................ 14
Transporting Outboard When Removed From Boat......................................... 14
Trailering Boat.................................................................................................. 15
Fuel and Oil
Fuel Requirements........................................................................................... 16
Oil Recommendation........................................................................................ 17
Mixing Fuel and Oil........................................................................................... 17
Filling Fuel Tank............................................................................................... 18
Features and Controls
Features and Controls...................................................................................... 19
Tilting Outboard................................................................................................ 20
Setting The Operating Angle Of Your Outboard .............................................. 21
eng v

Operation
Prestarting Check List.......................................................................................23
Operating in Freezing Temperatures................................................................ 23
Operating in Saltwater or Polluted Water......................................................... 23
Engine Break‑in Procedure...............................................................................24
Starting The Engine.......................................................................................... 24
Gear Shifting ‑ Models with Gear Shift............................................................. 27
Stopping The Engine ....................................................................................... 28
Emergency Starting.......................................................................................... 28
Maintenance
Outboard Care.................................................................................................. 30
Inspection and Maintenance Schedule ............................................................ 30
Top Cowl Removal And Installation.................................................................. 31
Exterior Care.....................................................................................................32
Flushing the Cooling System............................................................................ 32
Propeller Replacement..................................................................................... 32
Corrosion Control Anode.................................................................................. 34
Spark Plug Inspection And Replacement......................................................... 35
Engine Idle Speed Adjustment......................................................................... 36
Lubrication Points............................................................................................. 37
Gearcase Lubrication........................................................................................39
Submerged Outboard....................................................................................... 41
Storage
Storage Preparation..........................................................................................42
Protecting External Outboard Components...................................................... 42
Protecting Internal Engine Components........................................................... 42
Gearcase.......................................................................................................... 43
Positioning Outboard for Storage..................................................................... 43
Troubleshooting
Engine Will Not Start.........................................................................................44
Engine Runs Erratically.................................................................................... 44
Performance Loss.............................................................................................44
vi eng

Owner Service Assistance
Service Assistance........................................................................................... 45
Ordering Literature............................................................................................47
Maintenance Log
Maintenance Log.............................................................................................. 49
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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
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.
GENERAL INFORMATION
2 eng

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.
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.
c
a
b
53910
OFF
RUN
ATTACH LANYARD
GENERAL INFORMATION
eng 3

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.
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.
GENERAL INFORMATION
4 eng

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.
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.
GENERAL INFORMATION
eng 5

! 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
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co
co
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co
co
co
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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.
GENERAL INFORMATION
6 eng

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
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.
21626
a
b
ab
21628
GENERAL INFORMATION
eng 7

• 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
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.
GENERAL INFORMATION
8 eng

• 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.
• 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.
GENERAL INFORMATION
eng 9

• 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 this number for future reference. The serial number is
located on the outboard as shown.
a - Serial number
b - Model designation
c - Year manufactured
d - Certified Europe Insignia (as applicable)
- - - . - - -
XXXXXXX
-
XXXXX XX
XL
Mercury
Marine
Serial Number
Brunswick Corp.
Made in Japan
XX
XXXX XXX
HP XXX
LB XXX KG XXX
KW XXX
Model Number
b
c
a
d
63835
GENERAL INFORMATION
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