Gale Model 25D21 Outboard Motor Specs & Overview

Gale Products, a division of Outboard Marine Corporation (OMC), built robust, high-performing outboard motors that shared much of their internal engineering with Johnson and Evinrude models of the same era. The Gale 25D21 (part of the 22D17-21 / 25DL18-21 series) is a classic 25-horsepower twin-cylinder workhorse. Powered by a 35.7 cubic inch powerhead, this model offers full Forward-Neutral-Reverse gearshift controls and robust torque, making it a reliable performer for vintage runabouts, fishing boats, and utility craft.

Technical Specifications

• Model: Gale 25D21
• Horsepower: 25.0 HP @ 4,500 RPM (OBC Certified)
• Operating Range: 4,000 – 5,000 RPM
• Cylinders: 2-cylinder, 2-port, alternate firing
• Displacement: 35.7 cubic inches
• Bore & Stroke: 2-7/8″ Bore x 2-3/4″ Stroke
• Gear Ratio: 12:21
• Gearshift Control: Forward – Neutral – Reverse (FNR)
• Ignition System: Built-in flywheel magneto
• Carburetor: Float feed with high and low speed adjustable needles
• Speed Control: Synchronized spark and throttle with twist grip control
• Cooling System: Rubber blade combination displacement and centrifugal water pump
• Starter: Automatic rewind recoil starter
• Propeller: 3-blade, 10-3/8″ diameter x 12-1/2″ pitch
• Fuel Tank Capacity: 6 gallons (separate remote tank)
• Weight: 115 lbs. (without tank)
• Recommended Transom Height: 15″ (Standard) or 20″ (Long Shaft models)

Fuel Mix & Lubrication Guidelines

Proper fuel and oil ratios are critical for preserving vintage two-stroke powerheads like the Gale 25 HP:

• Fuel-to-Oil Ratio: Run a standard 24:1 gas-to-oil ratio (approx. 1 quart of oil to 6 gallons of gas, or 1/2 pint per gallon). This provides adequate lubrication for internal bushings and rod bearings.
• Fuel Recommendation: Use 87-octane non-ethanol (rec 90) fuel. Modern ethanol blends can damage vintage rubber fuel lines, carburetor floats, and pump diaphragms.
• Oil Type: Use a quality TC-W3 rated 2-stroke outboard motor oil.

Maintenance & Restoration Advice

Because Gale shared core components with OMC’s main product lines, finding service parts for the 25D21 is relatively straightforward. Keep these maintenance items in mind when restoring or tuning up your engine:

• Ignition System Tune-Up: Remove the flywheel to inspect the dual ignition coils, breaker points, and condensers. Old OMC armature coils frequently crack with age; replace them with modern OMC-style ignition coils and set breaker point gaps to 0.020 inches.
• Cooling System Service: The lower unit relies on a combination displacement and centrifugal water pump equipped with a flexible rubber impeller. Always replace the impeller during restoration before starting the motor to ensure proper cooling flow and prevent powerhead overheating.
• Carburetor Adjustments: Clean out varnish from the float bowl and passages. Initial setup for the needle valves generally starts at 1.5 turns open for the low-speed idle mixture and 3/4 to 1 turn open for the high-speed main jet needle, adjusted under actual load on the water.
• Gearcase Maintenance: Drain the lower unit oil and check for water contamination (milky appearance). Re-fill using modern 80W-90 marine hypoid gear lubricant, replacing the drain and fill plug seals to keep out water.