1968 Chrysler 20 HP Outboard Specs & Part Numbers
Technical Guide: 1968 Chrysler 20 HP Outboard Motor
The 1968 Chrysler 20 HP outboard motor is a classic twin-cylinder, two-stroke marine engine representing the golden era of Chrysler’s marine division. Following Chrysler’s acquisition of the West Bend Outboard Motor Company in 1965, these motors combined West Bend’s proven engineering with Chrysler’s styling and marketing power. Today, they are prized by vintage outboard enthusiasts for their simple design, power-to-weight ratio, and ease of maintenance.
This technical guide provides comprehensive specifications, maintenance parameters, and historical context for servicing and restoring this classic motor.
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1. Overview & Technical Specifications
The 1968 Chrysler 20 HP was offered in both manual (rope) start and electric start configurations, with standard (15-inch) and long (20-inch) shaft lengths. It is a loop-charged, twin-cylinder two-stroke powerhead known for its reliable, low-end torque.
| Specification | Value / Metric |
|---|---|
| Manufacturer | Chrysler Outboard Corporation (Hartford, Wisconsin) |
| Model Year | 1968 |
| Horsepower Rating | 20 HP @ 5,000 RPM |
| Engine Type | 2-Stroke, Twin-Cylinder, Reed Valve Intake |
| Displacement | 19.9 cubic inches (326 cc) |
| Bore & Stroke | 2.50 in. x 2.03 in. (63.5 mm x 51.5 mm) |
| Fuel-to-Oil Ratio | 50:1 (using modern TC-W3 2-stroke outboard oil and 87 octane unleaded gasoline) |
| Weight | Approx. 74 lbs (33.5 kg) for manual start, short shaft |
| Cooling System | Water-cooled (positive displacement impeller pump with bypass thermostat) |
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2. Common Maintenance & Tune-Up Specifications
Keeping a 1968 Chrysler 20 HP running optimally requires attention to its traditional magneto ignition system and fuel delivery components. Below are the precise mechanical settings required for a standard tune-up.
Ignition System
- Spark Plugs: Champion L82C (or modern equivalent QL82C for radio noise suppression). Historically, Champion L4J was specified.
- Spark Plug Gap: 0.030 inches (0.76 mm).
- Ignition Type: Flywheel Magneto with dual contact breaker points and condensers.
- Point Gap: 0.020 inches (0.51 mm) at high lobe.
- Timing: Fixed timing advance linked to the throttle cam. Adjust according to the marks on the armature plate under the flywheel.
Fuel & Carburetion
- Carburetor Type: Tillotson MD series or Carter float-feed side-draft carburetor.
- Initial Low-Speed Mixture Screw Setting: Gently seat the needle, then back out 1 to 1-1/4 turns. Fine-tune in the water with the engine warm and in forward gear.
- Fuel Pump: Diaphragm type, operated by crankcase pulses. Replacement diaphragms are still widely available as part of standard carburetor rebuild kits.
Lower Unit & Cooling
- Gearcase Lubricant: SAE 90 Outboard Gear Lubricant (Type C or standard premium marine gear lube). Do not use modern synthetic automotive gear lubes unless they are specifically rated for marine wet-running environments.
- Gearcase Capacity: Fill from the bottom drain hole until fluid exits the top vent hole (approx. 7-8 oz).
- Water Pump Impeller: The rubber impeller should be replaced every 2 to 3 seasons. If the motor has sat idle for several years, replace the impeller before attempting to run it to prevent dry-rotted rubber from breaking off and clogging the water passages.
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3. Notable Features & History
The West Bend Heritage
In 1965, the Chrysler Corporation sought a rapid entry into the booming recreational marine industry. They purchased the West Bend Outboard Motor Company based in Hartford, Wisconsin. The 1968 Chrysler 20 HP is a direct descendant of the highly successful West Bend 18 HP / 20 HP powerhead design. Chrysler modernized the exterior styling, optimized the carburetor configurations, and improved the corrosion resistance of the aluminum castings.
Styling & Aesthetics
The 1968 model year featured Chrysler’s iconic “white and black” corporate marine paint scheme. The clean, straight-line graphics on the aluminum cowl complemented the design trends of late-1960s boats. The lightweight fiberglass cowl (shroud) is easily removable via two side latches, providing excellent access to the entire powerhead for servicing.
Engineering Strengths & Weaknesses
- The Good: Excellent power-to-weight ratio. At around 74 pounds, it is significantly lighter than comparable 18-20 HP OMC (Evinrude/Johnson) models of the same era, which often weighed over 80-85 pounds. The simple, direct-actuating throttle linkage is highly reliable.
- The Bad: The ignition system is sensitive to dampness. Because the points and condensers are located under the flywheel, moisture intrusion can cause hard starting or spark loss on one cylinder. The splined driveshaft interface is also prone to rusting to the crankshaft if not properly greased with marine anti-seize during water pump service.
Pro-Tips for Owners & Restorers
- Always inspect the motor mounts: The rubber vibration-dampening mounts on these motors can soften or disintegrate over time due to exposure to fuel and oil leaks. Replacement mounts drastically improve steering control and decrease tiller vibration.
- Grounding the Coils: Ensure the external ignition coils have clean, paint-free ground contacts to the powerhead bracket. Poor grounds are the leading cause of intermittent spark issues on these models.