Mercury 25 Jet FourStroke Installation Manual
Operation
Maintenance
and
Installation
Manual
© 2018 Mercury Marine
25 Jet FourStroke
8M0145522 418 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.
California Proposition 65
WARNING: This product can expose you to chemicals including
gasoline engine exhaust, which is known to the State of
California to cause cancer and birth defects or other
reproductive harm. For more information go to
www.P65Warnings.ca.gov.
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
Watercraft Identification Number (WIN) or 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........................................................................................... 3
Protecting People in the Water........................................................................... 6
Wave and Wake Jumping................................................................................... 7
Safety Instructions for Hand‑Tilled Outboards.................................................... 7
Exhaust Emissions............................................................................................. 8
Selecting Accessories for Your Outboard......................................................... 10
Safe Boating Recommendations...................................................................... 10
Recording Serial Number................................................................................. 13
Model Year Production Code............................................................................13
Specifications....................................................................................................14
Component Identification.................................................................................. 15
Transporting
Trailering Boat/Outboard.................................................................................. 17
Fuel and Oil
Fuel Requirements........................................................................................... 18
Low Permeation Fuel Hose Requirement ........................................................ 19
EPA Pressurized Portable Fuel Tank Requirements........................................ 19
Fuel Demand Valve (FDV) Requirement.......................................................... 19
Mercury Marine's Pressurized Portable Fuel Tank........................................... 20
Filling Fuel Tank............................................................................................... 21
Engine Oil Recommendations.......................................................................... 21
Checking and Adding Engine Oil...................................................................... 22
Features and Controls
Remote Control Features................................................................................. 24
Tiller Handle Models......................................................................................... 24
Power Trim and Tilt (if Equipped)..................................................................... 30
Warning System............................................................................................... 32
Replaceable Jet Drive Shear Key..................................................................... 35
eng v
Operation
Prestarting Check List.......................................................................................36
Operating in Freezing Temperatures................................................................ 36
Operating in Saltwater or Polluted Water......................................................... 36
Operating in Shallow Water.............................................................................. 37
How the Jet Drive Operates..............................................................................37
Stopping the Boat in an Emergency................................................................. 39
Steering the Boat.............................................................................................. 39
Mooring the Boat.............................................................................................. 40
Water Intake Blockage......................................................................................40
Clearing A Lodged Impeller.............................................................................. 40
Prestarting Instructions..................................................................................... 41
Engine Break‑in Procedure...............................................................................42
Starting the Engine ‑ Remote Control Models.................................................. 42
Starting the Engine ‑ Tiller Handle Models....................................................... 44
Gear Shifting .................................................................................................... 47
Stopping the Engine ........................................................................................ 48
Emergency Starting.......................................................................................... 48
Maintenance
Cleaning Care Recommendations.................................................................... 50
EPA Emission Regulations............................................................................... 52
Inspection and Maintenance Schedule ............................................................ 53
Top Cowl Removal and Installation.................................................................. 54
Worn/Dull Impeller............................................................................................ 54
Impeller Clearance Adjustment.........................................................................55
Impeller Removal and Installation.....................................................................56
Shift Link Rod Adjustment................................................................................ 59
Battery Inspection ............................................................................................ 60
Fuel System...................................................................................................... 60
Steering Link Rod Fasteners............................................................................ 61
Corrosion Control Anode.................................................................................. 62
Spark Plug Inspection and Replacement..........................................................63
Fuse Replacement ‑ Electric Start Models....................................................... 64
Timing Belt Inspection...................................................................................... 65
Lubrication Points............................................................................................. 65
Checking Power Trim Fluid...............................................................................68
Changing Engine Oil ........................................................................................ 69
Submerged Outboard....................................................................................... 71
vi eng
Storage
Storage Preparation..........................................................................................72
Protecting External Outboard Components...................................................... 72
Protecting Internal Engine Components........................................................... 73
Jet Drive............................................................................................................73
Positioning Outboard for Storage..................................................................... 73
Battery Storage................................................................................................. 73
Troubleshooting
Starter Motor will not Crank the Engine (Electric Start Models)........................ 74
Engine Will Not Start.........................................................................................74
Engine Runs Erratically.................................................................................... 74
Engine Overspeed (Excessive RPM)............................................................... 75
Performance Loss.............................................................................................75
Battery Will Not Hold Charge............................................................................ 75
Owner Service Assistance
Service Assistance........................................................................................... 76
Ordering Literature............................................................................................78
Installation
Installation Information......................................................................................80
Top Cowl Removal and Installation.................................................................. 82
Lifting Outboard................................................................................................ 83
Determining the Mounting Height of the Outboard Jet .................................... 83
Fastening the Outboard.................................................................................... 85
Steering Bracket, Steering Cable Installation................................................... 87
Steering Link Rod Fasteners............................................................................ 88
Electrical Harness, Battery Connection, Fuel Tanks........................................ 91
Control Cable Installation..................................................................................94
Water Testing................................................................................................... 98
Maintenance Log
Maintenance Log............................................................................................ 100
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.
!
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.
N
63103
GENERAL INFORMATION
2 eng
Remote Steering Notice
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 nonlocking nuts. Nonlocking nuts may loosen and vibrate off,
allowing the link rod to disengage.
!
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.
a - Self‑locking nuts
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.
a
a
59490
GENERAL INFORMATION
eng 3
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
4 eng
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
eng 5
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 when boating in an area
where there might be people in the water.
Avoid shallow water or where any loose material such as sand, shells,
seaweed, grass, tree branches, etc., can be pulled in and expelled from the
pump as a high speed projectile.
WHILE BOAT IS STATIONARY
!
WARNING
Avoid injury resulting from contacting the rotating impeller or having hair,
clothing, or loose objects drawn into the water intake and wrapping around
the impeller shaft. Stay away from the water intake and never insert an object
into the water intake or water outlet nozzle when the engine is running.
Stop the engine immediately whenever a person is in the water near the boat.
The jet drive is always drawing water through the water intake when the engine
is running. Stay away from the water intake located under the jet drive and
never insert an object into the water intake or outlet nozzle when the engine is
running.
GENERAL INFORMATION
6 eng
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.
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 Installation ‑ Fastening the Outboard
for more complete installation information.
GENERAL INFORMATION
eng 7
!
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.
If an obstacle is struck at planing speed and the outboard is not securely
fastened to the transom, it is possible the outboard could lift off the transom
and land in the 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.
!
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
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co
co
co
co
co
co
co
co
co
co
co
co
co
co
co
co
co
co
GENERAL INFORMATION
8 eng
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:
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
eng 9
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
10 eng
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
eng 11
• 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.
GENERAL INFORMATION
12 eng
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)
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
24800
XXXXXXX
XXXXX XX
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
GENERAL INFORMATION
eng 13
Examples:
• XX = 2000
• HK = 2089
• AG = 2017
Specifications
Models 25
Power 18.4 kw (25 hp)
Full throttle RPM range 5000–5500 RPM
Idle speed in forward gear 850 ± 25 RPM
Number of cylinders 3
Piston displacement 526 cc (32.09 cid)
Cylinder bore 61 mm (2.40 in.)
Stroke 60 mm (2.36 in.)
Valve clearance (cold)
Intake valve 0.13–0.17 mm (0.005–0.007 in.)
Exhaust valve 0.18–0.22 mm (0.007–0.008 in.)
Recommended spark plug NGK DCPR6E
Spark plug gap 0.8–0.9 mm (0.031–0.035 in.)
Recommended gasoline
Refer to Fuel and Oil
Recommended oil
Refer to Fuel and Oil
Recommended lubricant for
the jet pump driveshaft
bearing
Refer to Maintenance
Engine oil capacity 1.8 liter (1.9 US qt)
Battery rating
465 marine cranking amps (MCA) or 350 cold
cranking amps (CCA)
Emission control system
Electronic engine control (EC)
Multiport fuel injection (MFI)
GENERAL INFORMATION
14 eng
Component Identification
TILLER HANDLE/GAS ASSIST MODEL
a - Top cowl
b - Manual start handle
c - Engine stop switch
d - Throttle friction adjustment knob
e - Gear shift
f - Tilt support lever
g - Gas tilt assist lever
h - Jet drive housing
i - Water intake housing
j - Reverse gate
k - Water outlet housing
l - Chaps
m - Water pump indicator hole
n - Cowl latch
o - Warning light
a
b
c
e
f
g
i
h
k
m
p
r
o
q
d
l
n
j
24805
GENERAL INFORMATION
eng 15
p - Electric start button (electric start models)
q - Lanyard stop switch
r - Steering friction adjustment lever
POWER TRIM/REMOTE CONTROL MODEL
a - Transom brackets
b - Tilt support lever
c - Top cowl
d - Cowl latch
e - Bottom cowl
f - Auxiliary tilt switch
g - Chaps
h - Water outlet housing
i - Reverse gate
j - Water intake housing
k - Jet drive housing
a
b
c
e
h
i
j
k
g
f
d
24827
GENERAL INFORMATION
16 eng
Trailering Boat/Outboard
The boat should be trailered with the outboard tilted down in a vertical
operating position.
IMPORTANT: Do not rely on the power trim/tilt system or tilt support lever to
maintain proper ground clearance for trailering. The outboard tilt support lever
is not intended to support the outboard for 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.
TRANSPORTING
eng 17
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
18 eng
!
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.
Low Permeation Fuel Hose Requirement
Required for outboards manufactured for sale, sold, or offered for sale in the
United States.
• The Environmental Protection Agency (EPA) requires that any outboard
manufactured after January 1, 2009, must use low permeation fuel hose
for the primary fuel hose connecting the fuel tank to the outboard.
• Low permeation hose is USCG Type B1‑15 or Type A1‑15, defined as not
exceeding 15 g/m²/24 h with CE 10 fuel at 23 °C as specified in SAE J
1527 ‑ marine fuel hose.
EPA Pressurized Portable Fuel Tank Requirements
The Environmental Protection Agency (EPA) requires portable fuel systems
that are produced after January 1, 2011, for use with outboard engines to
remain fully sealed (pressurized) up to 34.4 kPa (5.0 psi). These tanks may
contain the following:
• An air inlet that opens to allow air to enter as the fuel is drawn out of the
tank.
• An air outlet that opens (vents) to the atmosphere if pressure exceeds
34.4 kPa (5.0 psi).
Fuel Demand Valve (FDV) Requirement
Whenever a pressurized fuel tank is used, a fuel demand valve is required to
be installed in the fuel hose between the fuel tank and primer bulb. The fuel
demand valve prevents pressurized fuel from entering the engine and causing
a fuel system overflow or possible fuel spillage.
FUEL AND OIL
eng 19
The fuel demand valve has a manual release. The manual release can be used
(pushed in) to open (bypass) the valve in case of a fuel blockage in the valve.
a - Fuel demand valve ‑ installed in the
fuel hose between the fuel tank and
primer bulb
b - Manual release
c - Vent/water drain holes
Mercury Marine's Pressurized Portable Fuel Tank
Mercury Marine has created a new portable pressurized fuel tank that meets
the preceding EPA requirements. These fuel tanks are available as an
accessory or are provided with certain portable outboard models.
SPECIAL FEATURES OF THE PORTABLE FUEL TANK
• The fuel tank has a two‑way valve which allows air to enter the tank as
the fuel is drawn to the engine, and also opens to vent to the atmosphere
if internal pressure in the tank exceeds 34.4 kPa (5.0 psi). A hissing noise
may be heard as the tank vents to the atmosphere. This is normal.
• The fuel tank includes a fuel demand valve that prevents pressurized fuel
from entering the engine and causing a fuel system overflow or possible
fuel spillage.
• When installing the fuel tank cap, turn the cap to the right until you hear a
click. This signals that the fuel cap is fully seated. A built‑in device
prevents overtightening.
• The fuel tank has a manual vent screw which should be closed for
transportation and open for operation and cap removal.
Since sealed fuel tanks are not vented, they will expand and contract as the
fuel expands and contracts during heating and cooling cycles of the outside air.
This is normal.
REMOVING THE FUEL CAP
a - Fuel cap
b - Manual vent screw
c - Tab lock
IMPORTANT: Contents may be under pressure. Rotate the fuel cap 1/4 turn to
relieve pressure before opening.
a
c
b
46453
a
b
c
46290
FUEL AND OIL
20 eng
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