1988 Johnson 50 VRO Manual

The 1988 Johnson 50 VRO is a 50 horsepower outboard motor featuring Variable Ratio Oiling (VRO) system, 2-cylinder configuration, 49.7 cubic inch displacement, loop charging, 50:1 fuel/oil ratio capability, thermostatically controlled cooling, CD ignition system, and corrosion protection. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Operation 6. Fuel System 7. Maintenance Schedule 8. VRO System 9. Winter Storage 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: VRO oil injection system, CD ignition, thermostatic cooling, corrosion protection anodes, 15-inch standard shaft.

Feature	Description
VRO System	Variable Ratio Oiling - automatic oil mixing
Displacement	49.7 cubic inches (814cc)
Cylinders	2-cylinder in-line
Ignition	CD capacitor discharge
Cooling	Thermostatically controlled water pump
Gear Ratio	1.85:1
Starting	Electric with manual backup
Weight	187 lbs (85 kg)
Shaft Length	15 inches standard
WOT RPM	4500-5500 RPM

Installation

Mount on transom following manufacturer specifications.

Select mounting location: Ensure transom can support 187 lbs weight.
Mount motor: Use appropriate mounting bolts and brackets.
Connect control cables: Attach throttle and shift cables.
Connect battery: Use marine battery with proper cables.
Connect fuel system: Attach fuel lines to VRO pump.

WARNING! Motor is heavy; use proper lifting equipment. Ensure transom is structurally sound.

First-Time Setup

Prepare motor for initial operation.

Prime VRO system: Fill oil tank and connect oil line.
Fuel system: Connect fuel line and prime system.
Battery connection: Connect positive and negative terminals.
Water supply: Connect flush port or lower unit in water.
Initial start: Follow break-in procedure for first 10 hours.

CAUTION! Never run motor without water supply. Follow break-in procedure carefully.

Specifications

Horsepower: 50 HP at 5000 RPM
Displacement: 49.7 cubic inches (814cc)
Cylinders: 2
Bore x Stroke: 3.375 x 2.775 inches
Ignition: CD capacitor discharge
Fuel System: VRO oil injection with 50:1 premix capability
Gear Ratio: 1.85:1
Alternator: 9 amp
Weight: 187 lbs
Full Throttle Range: 4500-5500 RPM

Controls and Operation

Standard marine control box with key switch, choke, throttle, and shift controls.

Control Functions: Key switch (Off/Run/Start), Choke button, Throttle only button, Neutral warm-up, Throttle friction adjustment.

Starting Procedure: Turn key to "Run", push key in for choke (cold start), turn to "Start". Shifting: Smooth movement between Forward/Neutral/Reverse. Trim: Manual trim adjustment with transom tilt pin.

Fuel System

VRO system automatically mixes oil with fuel. Can use premix 50:1 as backup.

Fuel tank: Use approved marine fuel tank.
Fuel lines: Connect to motor fuel pump.
Oil tank: Fill with TC-W3 certified oil.
Priming: Squeeze fuel line bulb until firm.

Tip: Always use fresh fuel and TC-W3 certified outboard oil.

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Every use: Check oil level, inspect for leaks.
100 hours/annually: Change gear lube, spark plugs.
300 hours: Water pump impeller replacement.
Annual: Corrosion anode inspection, fuel filter replacement.
Storage: Fog cylinders, stabilize fuel.

WARNING! Disconnect battery before maintenance. Use only marine-grade parts.

VRO System

Variable Ratio Oiling automatically adjusts oil ratio based on RPM.

VRO Operation: Monitors engine speed and load to deliver proper oil mixture. Warning System: Horn sounds if oil level low or system failure. Backup: Can run on 50:1 premix if VRO fails.

Winter Storage

Proper storage prevents damage during off-season.

Fog engine: Spray fogging oil through carburetor. Fuel system: Add stabilizer and run engine. Cooling system: Drain water from pump. Battery: Remove and store charged. Cover: Protect from elements.

CAUTION! Never store with water in cooling passages to prevent freeze damage.

Regulatory Information

US Coast Guard approved. EPA certified for emissions. Manufactured by Outboard Marine Corporation. Meets 1988 marine engine standards. For technical support, contact authorized Johnson dealer or OMC customer service.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel, spark, or compression	Check fuel delivery, spark plugs, compression test.
VRO warning horn	Low oil or system failure	Check oil level; switch to premix if horn continues.
Overheating	Water pump or thermostat	Check water pump output; replace thermostat if stuck.
Poor performance	Fuel system or ignition	Check fuel filter, spark plugs, carburetor adjustment.
No charging	Alternator or rectifier	Test alternator output; check rectifier/regulator.

Reset: Disconnect battery to reset warning systems.

Service: Contact authorized Johnson dealer for major repairs.