1971 Chrysler 12 HP Outboard Specs & Part Numbers
Introduction
The 1971 Chrysler 12 HP outboard motor is a classic piece of marine engineering from the golden era of family boating. Produced during Chrysler Marine’s peak production years following their acquisition of West Bend, this lightweight, twin-cylinder two-stroke motor was a staple on lakes and rivers across North America. Prized for its simple design, excellent power-to-weight ratio, and distinct vintage styling, it remains a favorite among vintage outboard collectors and DIY mechanics today.
This technical guide provides comprehensive specifications, maintenance parameters, and historical context to help owners restore, maintain, and operate this classic outboard motor.
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1. Overview & Specifications
The 1971 Chrysler 12 HP (often designated under model series starting with 122, such as 122HA, 122HB, etc.) is an inline two-cylinder, loop-charged two-stroke engine. It features a lightweight aluminum block and a compact, low-profile cowl design.
| Specification | Value / Measurement |
|---|---|
| Power Output | 12 Horsepower @ 4,800 RPM |
| Engine Type | 2-Cylinder, 2-Stroke, Loop-Charged |
| Displacement | 14.1 cubic inches (231 cc) |
| Bore x Stroke | 2.125 inches x 2.000 inches |
| Fuel/Oil Ratio | 50:1 (50 parts unleaded gasoline to 1 part TC-W3 oil) |
| Recommended Fuel | 87 Octane (Non-Ethanol highly recommended) |
| Fuel Capacity | External tank (usually 3 or 6 gallon) with Chrysler-specific dual-line or single-line connectors |
| Weight | Approximately 64 lbs (29 kg) |
| Cooling System | Water-cooled via a rubber impeller located in the lower unit |
| Starting | Manual pull-start (recoil) |
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2. Common Maintenance & Tune-Up Specs
Keeping a 1971 Chrysler 12 HP running smoothly requires attention to its traditional ignition system and fuel delivery. Below are the critical tune-up measurements and maintenance specifications required for servicing.
Ignition System Specs
- Spark Plug Type: Champion L82C (or equivalent NGK B7HS)
- Spark Plug Gap: 0.030 inches (0.76 mm)
- Breaker Point Gap: 0.020 inches (0.51 mm) at high point of cam lobes
- Timing: Advanced timing is set mechanically via the throttle linkage and armature plate rotation. Timing marks are located on the flywheel and starter bracket.
Carburetor & Fuel System
- Carburetor Type: Tillotson or Carter side-draft design.
- Low-Speed Idle Mixture Adjustment: Gently turn the needle valve clockwise until seated, then back out 1 to 1-1/4 turns as an initial starting point. Adjust while the motor is warm and running in a test tank.
- High-Speed Jet: Most models from this year feature a fixed high-speed jet to prevent lean-run engine damage.
Gearcase & Lower Unit
- Gear Lubricant: Use high-quality Marine SAE 90 Outboard Gear Lube (Type C or Hypoid).
- Gearcase Capacity: Fill from the bottom drain hole until fluid exits the top vent plug hole. Approximately 5 to 6 fluid ounces.
- Water Pump Impeller: The impeller should be replaced every 1-2 seasons depending on use. When installing a new impeller, coat the inner housing with a thin layer of glycerin or soapy water (avoid grease, which can degrade the rubber) and rotate the driveshaft clockwise while sliding the housing down over the impeller.
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3. Notable Features & History
Origins and the West Bend Legacy
The roots of the 1971 Chrysler 12 HP outboard extend back to the West Bend Aluminum Company’s marine division. Chrysler purchased West Bend’s outboard operations in Hartford, Wisconsin, in 1965 to form “Chrysler Outboard Corporation.” Under Chrysler’s ownership, engineers refined the existing West Bend designs, improving reliability, corrosion resistance, and aesthetics while maintaining the lightweight construction that made them popular.
The “Low Profile” Design
One of the most praised design features of the Chrysler 12 HP is its extremely low-profile motor cover (cowl). Unlike bulkier competitor models of the early 1970s, the Chrysler 12 HP was engineered to sit low on the transom. This lowered the center of gravity of the boat, made the engine easier to lift and carry, and reduced interference with fishing lines cast over the stern.
Simplicity and Serviceability
Compared to modern outboards packed with computerized components, the 1971 Chrysler 12 HP is incredibly simple to service. The entire ignition system is housed directly under the flywheel, accessible with a basic flywheel puller. The magneto system relies on dual mechanical points and condensers, meaning the engine does not require an external battery or electrical system to run. If there is fuel, compression, and spark, this motor will run.
The Transition to Force Outboards
Chrysler continued to manufacture outboards throughout the 1970s until financial troubles forced the parent corporation to sell its marine division in 1984. The Hartford facility was sold to Bayliner, which rebranded the line as Force Outboards. Many of the base block designs and water pump components of the Force 9.9 and 15 HP outboards from the late 1980s and early 1990s can trace their lineage directly back to this 1971 Chrysler 12 HP platform.