1987 DT 140 Service Manual

The 1987 DT 140 is a 140 horsepower outboard motor manufactured by Suzuki Marine. This service manual covers maintenance, repair, and troubleshooting procedures for the DT 140 model year 1987. Below are key sections for specifications, maintenance procedures, troubleshooting, and technical data.

1. Specifications 2. Maintenance Schedule 3. Engine Systems 4. Fuel System 5. Electrical System 6. Cooling System 7. Lower Unit 8. Troubleshooting 9. Torque Specifications 10. Wiring Diagrams

Specifications

Technical specifications for the 1987 DT 140 outboard motor.

SpecificationValue
Engine TypeV6 Two-Stroke Outboard
Displacement1.8L (1796cc)
Bore x Stroke70mm x 78mm
Compression Ratio6.2:1
Weight192 kg (423 lbs)
Fuel SystemMikuni Carburetors (3)
Ignition SystemCDI Electronic
Starting SystemElectric Start
Gear Ratio2.07:1
WOT RPM Range5000-6000 RPM

Maintenance Schedule

Recommended maintenance intervals for the DT 140 outboard motor.

  1. Spark Plug Replacement: Every 100 hours or annually
  2. Gear Oil Change: Every 100 hours or annually
  3. Fuel Filter Replacement: Every 200 hours
  4. Water Pump Impeller: Every 2 years or 300 hours
  5. Thermostat Replacement: Every 2 years
  6. Carburetor Synchronization: Every 200 hours

WARNING! Always disconnect battery before performing maintenance. Use marine-grade lubricants only.

Engine Systems

Detailed information about engine components and systems.

CAUTION! Always use proper lifting equipment when handling engine.

Fuel System

Fuel system components and maintenance procedures.

  1. Carburetor Adjustment: Use synchronization tool for proper balance
  2. Fuel Pump: Diaphragm type, inspect for leaks annually
  3. Fuel Lines: Check for cracks and deterioration every season
  4. Fuel Filter: Replace element when restricted
  5. Oil Injection: Verify proper oil flow at all RPM ranges

Tip: Use only fresh gasoline with proper oil mixture for premix testing.

Electrical System

Electrical components and testing procedures.

ComponentSpecification
Alternator Output19 amps at 5000 RPM
Battery12V, minimum 70Ah marine battery
Spark Plug TypeNGK B8HS or equivalent
Spark Plug Gap0.7-0.8mm (0.028-0.031 in)
Starter Motor12V, 1.4 kW

Cooling System

Cooling system maintenance and troubleshooting.

  1. Water Pump Inspection: Check impeller for wear every season
  2. Thermostat: Test opening temperature (52°C/126°F)
  3. Tell-tale Stream: Verify strong water flow at all RPMs
  4. Overheat Warning: Test horn and sensor functionality
  5. Water Passages: Flush with fresh water after saltwater use

WARNING! Never run engine without water supply to prevent damage.

Lower Unit

Gearcase maintenance and service procedures.

Troubleshooting

Common problems and solutions for the DT 140.

SymptomPossible CauseCorrective Action
Engine won't startFuel delivery, spark, compressionCheck fuel flow, spark plugs, compression test
OverheatingWater pump, thermostat, blockageReplace impeller, test thermostat, clear water passages
Poor performanceCarburetion, ignition timingSynchronize carbs, check timing advance
Oil alarm soundsLow oil, sensor failureCheck oil level, test oil flow sensor
Gear shifting issuesCable adjustment, lower unitAdjust shift cable, inspect lower unit gears

Torque Specifications

Critical torque values for engine assembly.

ComponentTorque Value
Cylinder Head Bolts22-24 ft-lbs (30-33 Nm)
Spark Plugs18-22 ft-lbs (25-30 Nm)
Flywheel Nut72-87 ft-lbs (98-118 Nm)
Propeller Nut45-55 ft-lbs (61-75 Nm)
Gearcase Drain Plugs7-10 ft-lbs (10-14 Nm)

Wiring Diagrams

Electrical system schematics and component locations.

Service: Contact authorized Suzuki Marine dealer for technical support.

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