Johnson 9.9hp (4-Stroke) vs Mercury 9.8hp (2-Stroke)
9.9hp (4-Stroke)
9.8hp (2-Stroke)
| Spec | Johnson 9.9hp (4-Stroke) | Mercury 9.8hp (2-Stroke) |
|---|---|---|
| Power & Performance | ||
| Horsepower | 9.9 HP | 9.8 HP |
| Displacement | 302 cc ← | 179 cc |
| Configuration | 2 Cyl / Inline | 2 Cyl / Inline |
| Weights & Dimensions | ||
| Dry Weight | 44 kg (97 lbs) | 24 kg (53 lbs) ← |
| Mechanical & Electrical | ||
| Gear Ratio | 2.42 | 2.0 |
| Alternator | 144 W ← | 60 W |
| Fuel Delivery | Carbureted | Carbureted |
| Maintenance | ||
| Spark Plug | NGK CR6E | NGK B8HS |
| Engine Oil | 10W-30 Marine | TC-W3 2-Stroke |
Technical Comparison Analysis
Power & Displacement
Comparing the Johnson 9.9hp (4-Stroke) and Mercury 9.8hp (2-Stroke) shows a displacement difference of 123cc. The Johnson features a larger 302cc block, which typically provides superior low-end torque and better hole-shot performance when pushing heavy loads or reaching planning speeds.
Weight & Rigging
In terms of transom weight, the Mercury is the lighter option at 24kg, offering a weight saving of 20kg over its competitor. This weight reduction is critical for smaller hulls or boats with limited transom capacity where every kilogram affects the center of gravity and drainage efficiency.
Electrical & Features
For boats equipped with modern electronics, sonar, and shallow-water anchors, the Johnson offers the best charging performance with a 144W alternator. Choosing the right power-to-weight profile between these two 4-stroke engines depends heavily on your specific boat's displacement and daily power requirements.