Gale Model 25DEL21 Motor Specs & Overview

Gale Products, a specialized division of Outboard Marine Corporation (OMC), manufactured rugged, dependable outboard motors that shared substantial mechanical DNA with its sister brands, Johnson and Evinrude. Built to deliver reliable power at an accessible price point, the Gale 25DEL21 (25 HP) was a popular mid-century workhorse designed for family runabouts, fishing craft, and utility boats.

Key Technical Specifications

• Model: 25DEL21
• Horsepower: 25.0 HP @ 4,500 RPM (O.B.C. Certified)
• Operating RPM Range: 4,000 – 5,000 RPM
• Cylinders: 2 cylinders
• Bore & Stroke: 2-7/8″ bore x 2-3/4″ stroke
• Displacement: 35.7 cubic inches
• Powerhead Type: 2-cycle, 2-port, alternate firing
• Gear Ratio: 12:21
• Gearshift Control: Forward – Neutral – Reverse (F-N-R)
• Starter: Electric starting with automatic recoil rewind backup
• Ignition: Built-in flywheel magneto
• Carburetor: Float feed with adjustable high and low-speed needles
• Speed Control: Twist grip control with synchronized spark and throttle
• Cooling System: Combination rubber blade displacement and centrifugal water pump
• Propeller: 3-blade, 10-3/8″ diameter x 12-1/2″ pitch
• Fuel Tank Capacity: 6 gallons (separate pressurized or pump tank depending on setup)
• Transom Fitment: Standard 15″ or 20″ transom heights
• Weight: 126 lbs. (excluding fuel tank)

Engineering & Design Features

The Gale 25DEL21 features a twin-cylinder 35.7 cubic inch powerhead utilizing an alternate firing design, delivering smooth torque across its operating range. Convenient electric starting combined with a full Forward-Neutral-Reverse gearshift makes this model easy to operate. Because Gale motors were produced by OMC, many core internal components—such as ignition parts, lower unit gears, and carburetion hardware—are readily interchangeable with equivalent Johnson and Evinrude models of the same era.

Restoration, Maintenance & Fuel Mix Advice

• Fuel-to-Oil Ratio: Running the correct fuel mixture is critical to preserving vintage OMC powerheads. Use a 24:1 ratio of 87-octane ethanol-free gasoline to TC-W3 rated 2-stroke outboard oil (16 oz of oil per 3 gallons of gas, or 1 quart per 6-gallon tank). Avoid ethanol-blended fuels (E10/E15), as ethanol deteriorates original cork float coatings, fuel lines, and rubber gaskets.
• Ignition Tune-Up: The Universal Magneto under the flywheel utilizes dual ignition coils, points, and condensers. Original coils on these vintage motors frequently crack over time. Replace aged coils with modern OMC-style ignition coils and set the contact breaker point gaps precisely to .020 inches.
• Cooling System Care: Never run the engine out of water. The rubber combination displacement impeller should be replaced before putting an un-serviced motor into operation. A failed impeller will quickly overheat the cylinder head and damage powerhead gaskets.
• Carburetor Tuning: The float-feed carburetor features manual high and low-speed adjustment needles. For initial startup after a rebuild, set the low-speed needle to approximately 1.5 turns open and the high-speed needle to 3/4 turn open, adjusting for smooth idle and full-throttle performance once the motor reaches operating temperature under load.
• Gearcase Maintenance: Drain and inspect the lower unit gear oil annually. Inspect for milky oil, which indicates water leaking past the propeller shaft or drive shaft seals. Refill using standard marine marine Hi-Vis gear lubricant.