Johnson 50hp (4-Stroke) vs Mercury 45hp (Inline-4)
50hp (4-Stroke)
45hp (Inline-4)
| Spec | Johnson 50hp (4-Stroke) | Mercury 45hp (Inline-4) |
|---|---|---|
| Power & Performance | ||
| Horsepower | 50 HP | 45 HP |
| Displacement | 815 cc ← | 720 cc |
| Configuration | 3 Cyl / Inline | 4 Cyl / Inline |
| Weights & Dimensions | ||
| Dry Weight | 109 kg (240 lbs) | 72 kg (159 lbs) ← |
| Mechanical & Electrical | ||
| Gear Ratio | 2.27:1 | 2.0 |
| Alternator | 216 W ← | 113 W |
| Fuel Delivery | EFI | Carbureted |
| Maintenance | ||
| Spark Plug | NGK DCPR7E | NGK BUHW (Surface Gap) |
| Engine Oil | 10W-40 FC-W | TC-W3 2-Stroke |
Technical Comparison Analysis
Power & Displacement
Comparing the Johnson 50hp (4-Stroke) and Mercury 45hp (Inline-4) shows a displacement difference of 95cc. The Johnson features a larger 815cc 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 72kg, offering a weight saving of 37kg 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 216W 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.