1998+ Mercury Mariner 25HP Bigfoot Service Manual
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- 1998 Plus Mercury Mariner 25hp Bigfoot Service Manual
Original high quality 1998+ Mercury Mariner 25HP Bigfoot Service Manual.
Starting Model Year: 1998
Starting Serial Number: 0G590000
Manual is indexed, searchable, with high resolution diagrams and images making it simple to navigate, search and print any page in the manual or the whole manual.
Manual covers all aspects of servicing, scheduled repairs and procedures required to fix any problem that may arise.
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Reference and Info files
Reviews - Write a Review
Rated: 5 by: Keith Sorensen Posted: Monday, July 25, 2011 at 6:00PM
The book was exactly what I was looking for I have a 1999 big foot 25hp
I followed your directions and it just took seconds.
Thanks I am very happy
Rated: 5 by: steve Posted: Wednesday, August 3, 2011 at 03:42AM
Rated: 5 by: Neil Prowse Posted: Saturday, May 19, 2012 at 06:58AM
Rated: 5 by: Timothy Pauli Posted: Friday, August 11, 2023 at 09:46AM
Full list of manual chapters:
COVER
25 BigFoot FourStroke
Notice
Notice to Users of This Manual
Cleanliness and Care of Outboard Motor
Service Manual Outline
SPECIFICATIONS
Section 1A - Specifications
Table of Contents
Specifications
Propeller Information Chart
Mercury/Quicksilver Lubricants and Sealants
Torque Specifications
MAINTENANCE
Section 1B - Maintenance
Table of Contents
Special Tools
Inspection And Maintenance Schedule
Before Each Use
After Each Use
Every 100 Hours of Use or Once yearly, Whichever occurs first
Every 300 Hours of Use or Three Years
Before Periods of Storage
Flushing The Cooling System
Fuel System
Fuel Line Filter
Fuel Line Inspection
Corrosion Control Anode
Spark Plug Inspection
Battery Inspection
Fuse Replacement – Electric Start Models
Timing Belt Inspection
Lubrication Points
Checking Power Trim Fluid
Changing Engine Oil
Oil Changing Procedure
Changing Oil Filter
Oil Filling
Gear Case Lubrication
Draining Gear Case
Gear Case Lubricant Capacity
Checking Gear Case Lubricant Level and Refilling Gear Case
Storage Preparation
Fuel System
Protecting External Outboard Components
Protecting Internal Engine Components
Gear Case
Positioning Outboard for Storage
Battery Storage
GENERAL INFORMATION
Section 1C - General Information
Table of Contents
Serial Number Location
Conditions Affecting Performance
Weather
Boat
Engine
Following Complete Submersion
Model 25 (4-Stroke) Powerhead Front View
Model 25 (4-Stroke) Powerhead Starboard View
Model 25 (4-Stroke) Powerhead Port View
Model 25 (4-Stroke) Powerhead Top View
Model 25 (4-Stroke) Powerhead Aft View
Propeller Selection
Propeller Removal/Installation
Power Trim System
General Information
Power Trim Operation
Trim "In" Angle Adjustment
Trim Tab Adjustment
Compression Check
Cylinder Leakage Testing
Analysis
Painting Procedures
Decal Application
OUTBOARD MOTOR INSTALLATION
Section 1D - Outboard Motor Installation
Table of Contents
Installation Specifications
Lifting Outboard
Installing Outboard – Non Thumb Screw Models
Installing Outboard – Thumb Screw Models
Steering Cable
Steering Cable Seal
Steering Link Rod
Wiring Harness
Battery Cable Connections
Shift and Throttle Cable
Shift Cable Installation
Throttle Cable Installation
Trim-In Stop Adjustment – Power Trim Models
Trim Tab Adjustment
IGNITION
Section 2A - Ignition
Table of Contents
Specifications
Special Tools
Flywheel
Electrical Components
Ignition Description
Ignition Component Description
Electronic Control Module (ECM)
Crank Position Sensor
Stator Assembly
Flywheel Assembly
Ignition Coil
Ignition Test Procedures
Ignition Troubleshooting
Tool: Multimeter/DVA Tester 91-99750A1
Ignition Diagnostic Procedures
Recommended Test
Testing Ignition Components
Resistance Tests
Engine Coolant Temperature (ECT) Sensor
Flywheel Removal and Installation
Removal
Installation
Stator Removal and Installation
Timing Belt
(ECM) Removal and Installation
Ignition Coil Removal and Installation
Voltage Regulator Removal and Installation
Crank Position Sensor Removal and Installation
CHARGING AND STARTING SYSTEM
Section 2B - Charging and Starting System
Table of Contents
Specifications
Special Tools
Starter Motor
Battery
Recommended Battery
Operating Engine Without Battery
Battery Charging System Troubleshooting
Battery Charging System
Description (15 Ampere)
Wiring Diagram (15 Ampere)
Alternator System Test (6 Ampere Stator)
Alternator System Test (15 Ampere Stator)
Stator Ohms Test
Regulator/Rectifier (P/N 854514-1) Diode Test
Analog Meter
Digital Meter
Starting System Components
Description
Troubleshooting the Starting Circuit
Starter Solenoid Test
Starting Circuit Troubleshooting Flow Chart
Starter Motor
Removal
Disassembly
Cleaning and Inspection
Testing
Brush Replacement
Reassembly
Installation
TIMING, SYNCHRONIZING AND ADJUSTING
Section 2C - Timing, Synchronizing and Adjusting
Table of Contents
Specifications
Special Tools
Idle Speed Adjustment
WIRING DIAGRAMS
Section 2D - Wiring Diagrams
Table of Contents
Electric Start Power Trim Wiring Diagram
Electric Start Tiller Handle Wiring Diagram
Electric Start Wiring Diagram
Manual Start Wiring Diagram
FUEL PUMP
Section 3A - Fuel Pump
Table of Contents
Specifications
Fuel Pump (USA S/N 0T408999 and Below, Belgium S/N 0P153499 and Below)
Fuel Pump ( USA S/N 0T409000 and Up, Belgium S/N 0P153500 and Up)
Fuel Pump
Fuel Pump USA S/N 0T408999 and Below
Fuel Pump Belgium S/N 0P153499 and Below
Operation
Removal
Disassembly
Inspection
Reassembly
Installation
Fuel Pump
Fuel Pump USA S/N 0T409000 and Up
Fuel Pump Belgium S/N 0P153500 and Up
Operation
Removal
Disassembly
Cleaning/Inspection/Repair
Check Valve Inspection/Replacement
Assembly
Installation
CARBURETOR
Section 3B - Carburetor
Table of Contents
Specifications
Special Tools
Carburetor (USA S/N 0T408999 and Below, Belgium S/N 0T153499 and Below)
Carburetor (USA S/N 0T409000 and Up, Belgium S/N 0P153500 and Up)
Intake
Carburetor Adjustments
Carburetor Removal
Carburetor Removal USA S/N 0T408999 and Below
Carburetor Removal Belgium S/N 0P153499 and Below
Carburetor Removal USA S/N 0T409000 and Up
Carburetor Removal Belgium S/N 0P153500 and Up
Carburetor Disassembly
Inspection
Carburetor Assembly
Carburetor Installation
Carburetor Installation USA S/N 0T408999 and Below
Carburetor Installation Belgium S/N 0P153499 and Below
Carburetor Installation USA S/N 0T409000 and Up
Carburetor Installation Belgium S/N 0P153500 and Up
EMISSIONS
Section 3C - Emissions
Table of Contents
Exhaust Emissions Standards
What Are Emissions?
Hydrocarbons – HC
Carbon Monoxide – CO
Oxides of Nitrogen - NOx
Controlling Emissions
Stoichiometric (14.7:1) Air/Fuel Ratio
Outboard Hydrocarbon Emissions Reductions
Stratified Vs Homogenized Charge
Homogenized Charge
Stratified Charge
Emissions Information
Manufacturer's Responsibility:
Dealer Responsibility:
Owner Responsibility:
EPA Emission Regulations:
Manufacturer's Certification Label:
Service Replacement Certification Label
Removal
Date Code Identification
Installation
Decal Location:
CYLINDER HEAD
Section 4A - Cylinder Head
Table of Contents
Specifications
Special Tools
Cylinder Head
Intake/Exhaust Valves
Camshaft/Oil Pump
Torque Sequence
Valve Clearance
Checking Valve Clearance
Adjusting Valve Clearance
Preparation for Cylinder Head Removal
Cylinder Head Removal
Cylinder Head Disassembly
Cleaning and Inspection
Rocker Shaft and Rocker Arm
Camshaft
Cylinder Head
Valves
Valve Springs
Cylinder Head Reassembly
Valve Installation
Camshaft Oil Seal Installation
Camshaft Installation
Rocker Arm Shaft Assembly
Rocker Arm Shaft Installation
Cylinder Head Gasket
Cylinder Head Installation
Cylinder Head Cover Installation
CYLINDER BLOCK / CRANKCASE
Section 4B - Cylinder Block/Crankcase
Table of Contents
Specifications
Special Tools
Crankshaft
Cylinder Block
Torque Sequence
Crankcase Cover
Exhaust Cover
Powerhead
Preparation for Powerhead Removal
Powerhead Removal
Removing Powerhead Components
Ignition Components
Charging and Starting System Components
Fuel Components
Harness and Battery Cable Removal
Oil Filter, Thermostat, and Exhaust Cover Removal
Cylinder Head Removal
Powerhead Disassembly
Crankshaft and Piston Removal
Piston Disassembly
Inspection
Cylinder Bore
Balance Piston
Crankcase Cover Bore
Piston
Piston Pin
Piston Rings
Crankshaft
Checking Main Bearing Clearance
Checking Connecting Rod Bearing Clearance
Thermostat
Oil Pressure Switch
Cylinder Block Reassembly
Selecting New Main Bearings
Main Bearing Installation
Selecting New Connecting Rod Bearings
Installing Connecting Rod Bearings
Connecting Rod Installation
Piston Ring Installation
Piston Installation
Crankshaft Installation
Crankcase Cover Installation
Cylinder Head Installation
Exhaust Cover Installation
Ignition Components
Charging and Starting System Components
Fuel Components
Powerhead Installation
Following Powerhead Installation
LUBRICATION
Section 4C - Lubrication
Table of Contents
Specifications
Oil Pump Removal
Oil Pump Disassembly
Cleaning and Inspection
Oil Pump Assembly
Oil Pump Installation
CLAMP / SWIVEL BRACKETS AND DRIVESHAFT HOUSING
Section 5A - Clamp/Swivel Brackets and Driveshaft Housing
Table of Contents
Specifications
Clamp Bracket (Remote Control)
Swivel Bracket
Swivel Bracket (Remote Control)
Driveshaft Housing
Adapter Plate
Steering Arm
POWER TRIM
Section 5B - POWER TRIM
Table of Contents
Special Tools
Power Trim
Power Trim Mounting
Theory Of Operation
Adjustments
Trimming Characteristics
Trailering Outboard
Tilting Outboard Up and Down Manually
Trim "In" Angle Adjustment
Power Trim Flow Diagrams - Trim Up
Power Trim Flow Diagrams - Tilt Up
Power Trim Flow Diagrams - Maximum Tilt
Power Trim Flow Diagrams - Trim Down
Power Trim Flow Diagrams - Shock Function Up
Power Trim Flow Diagrams - Shock Return Function
Power Trim Flow Diagrams - Manual Tilt
Troubleshooting
Preliminary Checks
Hydraulic System Troubleshooting Flow Chart
Troubleshooting the Power Trim Electrical System
Power Trim System Removal
Testing Power Trim System With Test Gauge Kit (91-52915A6)
"UP" Pressure Check
"DOWN" Pressure Check
Disassembly
Shock Rod Disassembly
Memory Piston Removal
Trim Motor Removal
Oil Pump Removal
Tilt Relief Valve Removal
Suction Seat Removal
Pilot Check Valve Assembly Removal
Cleaning/Inspection/Repair
Reassembly
Power Trim Reassembly
Tilt Relief Valve Reassembly
Suction Seat Reassembly
Pilot Check Valve Reassembly
Oil Pump Reassembly
Trim Motor Reassembly
Shock Rod Reassembly
Shock Rod Installation
Manual Release Valve Installation
Bleeding Power Trim Unit
Power Trim System Installation
GAS ASSIST MANUAL TILT
Section 5C - Gas Assist Manual Tilt
Table of Contents
Clamp Bracket
Hydraulic Assist Adjustments
Manual Trim System Removal
Manual Trim System Installation
LOWER UNIT
Lower Unit
Table of Contents
Specifications
Special Tools
Gear Housing (Driveshaft) (2.42:1 Gear Ratio)
Gear Housing (Propeller Shaft) (2.42:1 Gear Ratio)
General Service Recommendations
Bearings
Seals
Draining and Inspecting Gear Lubricant
Gear Housing Removal
2-Stroke Models
4-Stroke Models
Disassembly
Water Pump
Water Pump Seals
Inspection
Upper Drive Shaft Bearing
Pinion Gear Bearing
Pinion Gear
Forward Gear
Shift Shaft
Propeller Shaft Disassembly
Propeller Shaft and Carrier Inspection
Clutch
Cam Follower
Reverse Gear
Reverse Gear Bearing
Bearing Carrier
Gear Housing Reassembly
Shift Shaft Assembly
Pinion Bearing Race
Forward Gear
Pinion Gear/Drive Shaft Assembly
Propeller Shaft
Bearing Carrier
Water Pump
Gear Housing Pressure Test
Gear Housing Installation
Filling Gear Housing with Lubricant
Installing Gear Housing to Drive Shaft Housing
Trim Tab Adjustment and Replacement
TROTTLE / SHIFT LINKAGE
Section 7A - Throttle/Shift Linkage
Table of Contents
Linkage
Shift Cable Installation
Throttle Cable Installation
TILLER HANDLE
Section 7B - Tiller Handle
Table of Contents
Tiller Handle
Throttle Cable Adjustment
Tiller Handle Assembly Removal
Tiller Handle Disassembly
Tiller Handle Reassembly
Tiller Handle Installation
MANUAL STARTER
Manual Starter
Table of Contents
Manual Starter
Manual Starter Removal
Manual Starter Disassembly
Cleaning and Inspection
Rewind Starter Reassembly
Adjusting Rewind Spring Tension
Manual Starter Installation
Interlock Cable Adjustment
COLOR DIAGRAMS
Color Diagrams
Table of Contents
25 Bigfoot (4-Stroke) Remote Control Electric 2002 Model Year USA S/N 0G760300 and up Belguim S/N 0P059000 and up
25 Bigfoot (4 Stroke) Tiller Handle Electric 2002 Model Year USA S/N 0G760300 and up Belguim S/N 0P059000 and up
25 Bigfoot (4 Stroke) Remote Control Electric (Gas Assist) 2002 Model Year USA S/N 0G760300 and up Belguim S/N 0P059000 and up
25 Bigfoot (4 Stroke) Tiller Handle Manual 2002 Model Year USA S/N 0G760300 and up Belguim S/N 0P059000 and up
25 (4-Stroke) Oil Flow Diagram
25 (4-Stroke) Water Flow Diagram
