1967 Mercury 20 HP Merc 200 Outboard Specs & Part Numbers
The 1967 Mercury 20 HP (Merc 200) is a legendary twin-cylinder outboard motor produced during the golden era of Kiekhaefer Mercury engineering. Celebrated for its impressive power-to-weight ratio, sleek “Phantom Black” aesthetic, and reliable performance, this motor remains a favorite among vintage marine enthusiasts and restoration hobbyists today.
This technical guide provides comprehensive specifications, maintenance parameters, and historical context to help you service, restore, or operate this classic powerhead.
Overview & Technical Specifications
The Merc 200 is a loop-charged, two-stroke inline-two engine utilizing a lightweight die-cast aluminum block. Below are the core engineering specifications for the 1967 production model:
| Parameter | Specification / Value |
|---|---|
| Manufacturer | Kiekhaefer Mercury (Fond du Lac, Wisconsin, USA) |
| Model Designation | Merc 200 (20 HP) |
| Production Year | 1967 |
| Horsepower Rating | 20 HP @ 5,000 to 5,500 RPM |
| Cylinders | 2 (Inline configuration) |
| Displacement | 22.0 cubic inches (360.5 cc) |
| Bore x Stroke | 2.50 inches x 2.25 inches (63.5 mm x 57.15 mm) |
| Fuel/Oil Ratio | 50:1 (Unleaded Gasoline to TC-W3 Outboard Engine Oil) |
| Fuel Induction | Single Reed-Valve, Tillotson Carburetor (Series AJ or KB) |
| Starting System | Manual recoil rope starter (Electric start optional on some sub-models) |
| Approximate Weight | 74 lbs (33.5 kg) for short shaft models |
Common Maintenance & Tune-up Specs
To keep the Merc 200 running smoothly, routine ignition, carburetion, and cooling system maintenance must be performed. Use the following precise specifications for tune-ups:
Ignition System
Depending on the specific serial number range, 1967 models came equipped with either a Phelon Makerpoint Magneto system or the early Thunderbolt Phase I Capacitive Discharge (CD) ignition system. The specifications below focus primarily on the widely-distributed dual-breaker point systems.
| Maintenance Item | Specification |
|---|---|
| Spark Plug Type | Champion L77JC4 (or NGK B7HS / BP8H-N-10) |
| Spark Plug Gap | 0.030 inches (0.76 mm) |
| Breaker Point Gap | 0.020 inches (0.51 mm) |
| Timing | Set timing pointer to the factory-marked timing lines on the flywheel cowl bracket at Top Dead Center (TDC). |
Carburetor Tuning (Tillotson)
For standard servicing of the Tillotson carburetor integrated into the 1967 Merc 200, use these baseline settings:
- Low-Speed Idle Mixture Screw: Gently turn the needle clockwise until it bottoms out (do not force it), then turn it counter-clockwise 1 to 1-1/4 turns out. This is your baseline starting point. Adjust while the engine is warm and running in gear.
- Float Height: Float level should be set parallel to the gasket surface of the fuel bowl cover when inverted.
Lower Unit & Cooling System
Operating a dry lower unit or a degraded water pump impeller will quickly cause catastrophic engine failure. Ensure the following maintenance specs are met annually:
| Component | Maintenance Spec & Part Numbers |
|---|---|
| Water Pump Impeller | OEM Part No: 47-89981T1 / Sierra Replacement No: 18-3007 |
| Gearcase Lubricant Type | High-quality SAE 90 Outboard Gear Lube (Quicksilver Premium Gear Lube) |
| Gearcase Oil Capacity | Approximately 6.0 fluid ounces (177 ml) |
| Propeller Shaft Splines | 8-Spline shaft. Apply marine-grade anti-seize or 2-4-C grease during assembly. |
Notable Features & History
The Kiekhaefer Mercury company, led by the legendary and uncompromising Carl Kiekhaefer, was renowned for engineering high-performance outboards that outperformed rivals like OMC (Evinrude/Johnson) in pure speed and innovation. The 1967 Merc 200 is a prime example of this engineering philosophy.
Propeller-Hub Exhaust (Jet-Prop)
One of Mercury’s most revolutionary contributions to outboard design was the integration of Jet-Prop exhaust. By routing the engine exhaust through the center of the propeller hub, Kiekhaefer’s design team buried engine noise and exhaust gases deep underwater. This system also improved engine breathing efficiency and reduced hydrodynamic drag, a massive competitive advantage in 1967.
The Phantom Black Styling
By 1967, Mercury had fully embraced its iconic “Phantom Black” paint scheme, adorned with striking chrome and red wrap-around cowls. The 1967 model featured the highly-coveted “wrap-around” faceplate design, which made accessing the spark plugs, carburetor, and magneto assembly relatively straightforward by unlatching and removing the outer cowlings.
Rotary Valve / Reed Valve Induction
Unlike many flathead or piston-ported competitors of the era, the 1967 Merc 200 utilized highly efficient internal reed blocks. This design ensured instantaneous throttle response and superior low-end torque, allowing small utility boats, runabouts, and family fishing boats to transition to plane quickly.
Legacy and Collectibility
Today, the 1967 Merc 200 20 HP is highly sought-after by vintage outboard collectors. Thanks to its lightweight design (around 74 lbs), it remains remarkably portable for a 20 HP motor. If properly maintained—specifically ensuring the cooling passages are free of salt/silt deposits and the ignition points are clean—these motors are incredibly durable and can easily run for another generation.