Mercury 9.8hp (2-Stroke) vs Johnson 9.9hp (4-Stroke)

Mercury

9.8hp (2-Stroke)

1990 · 9.8 HP · 2-Stroke
VS
Johnson

9.9hp (4-Stroke)

2005 · 9.9 HP · 4-Stroke
Spec Mercury 9.8hp (2-Stroke) Johnson 9.9hp (4-Stroke)
Power & Performance
Horsepower 9.8 HP 9.9 HP
Displacement 179 cc 302 cc ←
Configuration 2 Cyl / Inline 2 Cyl / Inline
Weights & Dimensions
Dry Weight 24 kg (53 lbs) ← 44 kg (97 lbs)
Mechanical & Electrical
Gear Ratio 2.0 2.42
Alternator 60 W 144 W ←
Fuel Delivery Carbureted Carbureted
Maintenance
Spark Plug NGK B8HS NGK CR6E
Engine Oil TC-W3 2-Stroke 10W-30 Marine

Technical Comparison Analysis

Power & Displacement

Comparing the Mercury 9.8hp (2-Stroke) and Johnson 9.9hp (4-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 2-stroke engines depends heavily on your specific boat's displacement and daily power requirements.