Gale Model 25D20 Outboard Motor Specs & Overview

The Gale Model 25D20 is a classic 25-horsepower outboard motor manufactured by Gale Products, a division of Outboard Marine Corporation (OMC). Renowned for producing reliable, budget-friendly alternatives to OMC’s primary Evinrude and Johnson lines, Gale manufactured outboards both under their own name (such as the Buccaneer series) and for major department store brands like Montgomery Ward (Sea King). Powered by a robust 35.7 cubic inch twin-cylinder powerhead, the 25D20 delivers dependable mid-range performance for vintage runabouts, fishing boats, and utility craft.

Technical Specifications

• Model: Gale 25D20
• Horsepower: 25.0 HP @ 4,500 RPM (O.B.C. Certified)
• Operating RPM Range: 4,000 – 5,000 RPM
• Displacement: 35.7 cubic inches
• Cylinders: 2-cylinder, alternate firing
• Powerhead Type: 2-cycle, 2-port
• Bore & Stroke: 2-7/8″ Bore x 2-3/4″ Stroke
• Gear Ratio: 12:21
• Propeller: 3-blade, 10-3/8″ diameter x 12-1/2″ pitch
• Cooling System: Rubber blade combination displacement and centrifugal water pump
• Ignition System: Built-in flywheel magneto
• Carburetion: Float feed with adjustable high and low-speed fuel mixture needles
• Speed Control: Synchronized spark and throttle with twist-grip handle
• Gearshift Control: Full Forward-Neutral-Reverse (F-N-R)
• Starting System: Automatic rewind manual starter
• Fuel Tank Capacity: 6 gallons (remote tank)
• Recommended Transom Height: 15″ standard / 20″ long shaft
• Weight: 115 lbs (excluding fuel tank)

2-Stroke Fuel/Oil Mixture Requirements

Because the 35.7 cubic inch OMC powerhead of this era relies heavily on adequate lubrication for internal plain bushings and roller bearings, running the correct oil mix is critical to engine longevity.

• Recommended Fuel Mix: 24:1 ratio (1 quart / 32 oz of high-quality TC-W3 outboard oil per 6 gallons of regular gasoline, or 1/2 pint per gallon).
• Fuel Selection: Use 87-octane ethanol-free gasoline whenever possible. Ethanol attracts water and degrades vintage rubber fuel lines, carburetor diaphragms, and cork floats.
• Caution: Do not run modern 50:1 fuel mixtures in this engine. Running a leaner oil mix will cause severe overheating and premature wrist-pin or crankshaft bearing failure.

Maintenance & Restoration Guidelines

Restoring or maintaining a Gale 25D20 is straight-forward due to its mechanical simplicity and parts interchangeability with standard OMC components of the mid-1950s. Key area checkouts include:

1. Ignition System Maintenance
Remove the flywheel to inspect the magneto components. Vintage OMC coils frequently crack due to age and temperature exposure. Replace cracked coils, clean contact points (gap to .020″), and install new condensers and spark plugs (typically Champion J6C or equivalent gapped to .030″).

2. Cooling System & Water Pump
Never start the motor without replacing the rubber water pump impeller first, especially if the motor has been sitting idle. Dried or brittle rubber blades can break off and clog internal cooling passages. Always test run the motor in a water bucket or tank to verify strong water discharge.

3. Carburetor Rebuild & Fuel Lines
Disassemble the float-feed carburetor, solvent-clean all internal passages, and install fresh fuel-resistant seals. If the original float is made of shellac-coated cork, replace it with a modern alcohol-resistant float. Inspect and replace all vintage rubber fuel lines with modern USCG-approved fuel hoses.

4. Lower Unit & Gearcase Service
Drain the gearcase lubricant and inspect for metal shavings or water intrusion (milkiness). Replace the lower unit seals and driveshaft seals if leakage is present. Refill the lower unit with quality marine gear lube (Type C or standard marine outboard gear lube).