1987 Yamaha 225 HP Service Manual

The 1987 Yamaha 225 HP outboard motor is a high-performance marine engine featuring V6 configuration, oil injection system, electric start, power trim and tilt, CD ignition system, thermostatically controlled cooling, and corrosion-resistant construction. This comprehensive service manual covers maintenance procedures, troubleshooting, repair instructions, and specifications for proper operation and longevity. Below are key sections for specifications, maintenance, troubleshooting, and repair procedures.

1. Specifications 2. Maintenance Schedule 3. Engine Systems 4. Fuel System 5. Ignition System 6. Cooling System 7. Electrical System 8. Lower Unit 9. Power Trim & Tilt 10. Troubleshooting 11. Repair Procedures

Specifications

Technical specifications for the 1987 Yamaha 225 HP outboard motor.

SpecificationDetails
Engine TypeV6, 2-stroke outboard
Displacement3.1L (189.7 cubic inches)
Bore x Stroke92mm x 78mm
Compression Ratio6.0:1
Fuel SystemOil injection with 6 carburetors
Ignition SystemCDI (Capacitor Discharge Ignition)
Starting SystemElectric start
Gear Ratio1.86:1
WeightApprox. 485 lbs (220 kg)
Recommended OilYamalube 2-stroke outboard oil

Maintenance Schedule

Regular maintenance intervals for optimal performance and longevity.

  1. Every 100 hours or annually: Change gearcase oil, inspect spark plugs.
  2. Every 200 hours: Replace water pump impeller, inspect fuel filters.
  3. Every 300 hours: Clean and synchronize carburetors, inspect fuel pumps.
  4. Annually: Flush cooling system, inspect electrical connections.
  5. Every 2 years: Replace thermostat, inspect power trim fluid.

WARNING! Always disconnect battery before performing maintenance. Use proper safety equipment.

Engine Systems

Overview of major engine systems and components.

Fuel System

Fuel delivery and carburetion system components and service.

  1. Fuel Pump: Diaphragm type with pulse operation
  2. Carburetors: 6 constant-velocity carburetors
  3. Fuel Filters: Replace every 200 hours or when clogged
  4. Oil Injection: Automatic mixing with separate oil tank
  5. Fuel Lines: Inspect for cracks and deterioration

CAUTION! Use only fresh fuel and proper oil mixture. Avoid ethanol blends when possible.

Ignition System

CD ignition system components and testing procedures.

Components: CDI unit, trigger coils, charge coils, spark plugs (NGK BU8H), ignition coils.

Testing: Use multimeter to check resistance values. Charge coil: 540-660 ohms. Trigger coil: 9-13 ohms. Ignition coil primary: 0.18-0.26 ohms. Spark plug gap: 0.9-1.0mm.

Cooling System

Water-cooling system maintenance and service.

  1. Flush system after saltwater use with fresh water.
  2. Replace water pump impeller every 200 hours or 2 years.
  3. Test thermostat operation at 43-48°C (opens).
  4. Inspect tell-tale stream for proper water flow.
  5. Check for debris in water intake screens.

Tip: Always run engine with water supply when testing on land.

Electrical System

Electrical components and wiring specifications.

ComponentSpecification
Starter Motor12V, 1.4kW
Alternator12V, 16 amp output
Battery12V, minimum 70Ah
FusesMain: 20A, Trim: 20A
Voltage RegulatorIntegrated with CDI unit

Lower Unit

Gearcase and propeller specifications and service.

  1. Gearcase Oil Capacity: 650ml
  2. Propeller Shaft: Splined, 15-tooth
  3. Gear Ratio: 1.86:1
  4. Shift Mechanism: Mechanical cable operation
  5. Propeller Selection: Consult performance charts

WARNING! Always check for fishing line around propeller shaft seal.

Power Trim & Tilt

Hydraulic trim and tilt system maintenance.

Fluid Type: ATF Dexron II/III. Fluid Capacity: 385ml. System Pressure: Trim - 1800-2200 psi, Tilt - 2400-2800 psi.

Bleeding Procedure: Cycle system fully several times, check fluid level, top up as needed.

Troubleshooting

Common problems and diagnostic procedures.

SymptomPossible CauseCorrective Action
Engine won't startFuel, spark, or compressionCheck fuel delivery, spark plugs, compression test
Poor performanceCarburetion, ignition timingClean carbs, check timing, inspect reeds
OverheatingWater pump, thermostatReplace impeller, test thermostat
No oil injectionOil pump, lines, sensorCheck oil pump operation, inspect lines
Electrical issuesBattery, connections, statorTest battery, clean connections, check stator

Repair Procedures

Step-by-step repair instructions for major components.

  1. Carburetor overhaul: Disassemble, clean, replace gaskets, reassemble
  2. Water pump replacement: Remove lower unit, replace impeller and housing
  3. Thermostat replacement: Remove housing, replace thermostat and gasket
  4. Spark plug replacement: Remove old plugs, gap new plugs, install
  5. Gearcase service: Drain oil, inspect gears, refill with new oil

Service: Contact authorized Yamaha dealer for complex repairs. Use genuine Yamaha parts.

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