Mercury SeaPro 40hp vs Johnson 40hp (2-Stroke)

Mercury

SeaPro 40hp

2005 · 40 HP · 2-Stroke
VS
Johnson

40hp (2-Stroke)

1978 · 40 HP · 2-Stroke
Spec Mercury SeaPro 40hp Johnson 40hp (2-Stroke)
Power & Performance
Horsepower 40 HP 40 HP
Displacement 644 cc 737 cc ←
Configuration 2 Cyl / Inline-3 2 Cyl / Inline
Weights & Dimensions
Dry Weight 75 kg (165 lbs) 64 kg (141 lbs) ←
Mechanical & Electrical
Gear Ratio 1.92 2.42
Alternator 210 W ← 144 W
Fuel Delivery EFI Carbureted
Maintenance
Spark Plug NGK BP8H-N-10 Champion QL77JC4
Engine Oil TC-W3 2-Stroke

Technical Comparison Analysis

Power & Displacement

Comparing the Mercury SeaPro 40hp and Johnson 40hp (2-Stroke) shows a displacement difference of 93cc. The Johnson features a larger 737cc 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 Johnson is the lighter option at 64kg, offering a weight saving of 11kg 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 Mercury offers the best charging performance with a 210W 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.