1987 Mercury 80 HP Outboard Manual

The 1987 Mercury 80 HP Outboard is a powerful marine engine featuring a 3-cylinder design, oil injection system, 80 horsepower output, electric start, power trim and tilt, thermostatically controlled cooling, CD ignition system, and single-lever control operation. This manual covers safety procedures, operation guidelines, maintenance schedules, troubleshooting, and technical specifications for proper use and care of your outboard motor.

1. Features at a Glance 2. Installation 3. Operation Guidelines 4. Specifications 5. Controls and Features 6. Maintenance Schedule 7. Fuel System 8. Electrical System 9. Cooling System 10. Storage & Winterization 11. Troubleshooting

Features at a Glance

Key components: 3-cylinder engine block, oil injection system, power trim/tilt, electric start, single-lever control, CD ignition, water pump cooling.

Feature	Description
Engine Type	3-cylinder, 2-stroke outboard
Horsepower	80 HP at 5000 RPM
Displacement	84.9 cubic inches (1392cc)
Starting System	Electric start with alternator
Fuel System	Oil injection with fuel pump
Ignition System	CD capacitor discharge
Gear Ratio	2.07:1
Trim System	Power trim and tilt
Weight	Approximately 248 lbs (112 kg)
Propeller	13-1/4" diameter standard

Installation

Proper installation ensures optimal performance and safety.

Select appropriate transom: Ensure transom height matches engine specifications.
Mounting: Use correct mounting bolts and follow torque specifications.
Steering connection: Connect steering system according to boat manufacturer guidelines.
Control installation: Install single-lever remote control at helm position.
Electrical connections: Connect battery with proper polarity and fuse protection.

WARNING! Engine is heavy; use proper lifting equipment. Ensure all connections are secure before operation.

Operation Guidelines

Follow these procedures for safe and efficient operation.

Pre-start check: Verify fuel level, oil level, and cooling water intake.
Starting procedure: Set control to neutral, push key in to choke if cold, turn key to start.
Warm-up: Allow engine to warm up at idle for 2-3 minutes before applying throttle.
Shifting: Use smooth, deliberate movements when shifting between forward, neutral, and reverse.
Shutdown: Allow engine to idle briefly before turning off to stabilize temperatures.

CAUTION! Always operate in well-ventilated areas. Carbon monoxide poisoning can occur in enclosed spaces.

Specifications

Model Year: 1987
Engine Type: 3-cylinder, loop-charged two-stroke
Bore x Stroke: 3.50" x 2.90" (89mm x 74mm)
Full Throttle RPM: 5000-5600 RPM
Fuel/Oil Ratio: 50:1 (with oil injection functioning)
Alternator Output: 10 amps
Spark Plug: Champion L77JC4 or equivalent
Gap Setting: 0.030" (0.76mm)
Recommended Fuel: 87 octane regular unleaded

Controls and Features

Understanding your outboard's controls ensures safe operation.

Single-Lever Control: Combines throttle and shift functions in one lever. Push forward for forward gear with increasing throttle, pull back for reverse.

Power Trim/Tilt: Button controls on remote or engine for adjusting engine angle while underway (trim) and raising engine for trailering (tilt).

Choke: Built into key switch - push key in while turning to activate choke for cold starts.

Emergency Stop Switch: Clip must be attached to operator for engine to run.

Maintenance Schedule

Regular maintenance ensures longevity and reliability.

Interval	Service Required
Every 100 hours	Change gear lube, inspect spark plugs
Every 200 hours	Replace water pump impeller
Annually	Check corrosion anode, lubricate fittings
Every 2 years	Replace fuel lines and filter
As needed	Check propeller for damage

Tip: Keep maintenance records for warranty and resale value.

Fuel System

The oil injection system provides automatic oil mixing.

Fuel tank: Use clean, approved marine fuel tanks.
Oil reservoir: Keep filled with Mercury/Quicksilver TC-W3 certified oil.
Priming: Use primer bulb to fill fuel lines before starting.
Filter: Replace fuel filter annually or if contamination is suspected.
Venting: Ensure fuel tank vent is open during operation.

WARNING! Gasoline is highly flammable. No smoking during refueling. Check for leaks regularly.

Electrical System

12-volt DC system with alternator charging.

Battery: Use marine starting battery with minimum 450 CCA.
Connections: Keep battery terminals clean and tight.
Fuses: Check main fuse (20 amp) if electrical systems fail.
Ignition: CD system provides hot spark for reliable starting.
Charging: Alternator maintains battery during operation.

Cooling System

Thermostatically controlled raw water cooling.

Water pump impeller should be replaced every 200 hours or 2 years. Signs of overheating include reduced tell-tale stream or steam from relief holes. Always check water output from tell-tale after starting.

CAUTION! Never run engine without water supply. Severe damage will occur quickly.

Storage & Winterization

Proper storage prevents damage during off-season.

Fuel system: Add fuel stabilizer and run engine to distribute.
Fogging: Spray fogging oil into carburetors before final shutdown.
Cooling: Flush with fresh water and drain completely.
Battery: Remove and store fully charged in cool, dry location.
Exterior: Wash thoroughly and apply protective wax.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel, spark, or compression issue	Check fuel supply, spark plugs, and kill switch
Overheating	Water pump or thermostat	Check water pump impeller, thermostat operation
Poor performance	Fuel restriction or ignition	Inspect fuel filter, spark plugs, carburetion
Oil alarm sounds	Low oil level or pump failure	Check oil reservoir, inspect oil injection system
Vibration	Propeller damage or imbalance	Inspect propeller for damage, check mounting

Service: Contact authorized Mercury Marine dealer for major repairs.

Parts: Use genuine Mercury replacement parts for optimal performance.