Description

The Yamaha 90hp 2-stroke is a legendary, lightweight, 3-cylinder outboard motor renowned for its incredible power-to-weight ratio and simplicity. Weighing around 261 lbs (119 kg), it is mostly carbureted and features “Precision Blend” oil injection. While it excels in performance, it requires regular maintenance and consumes more fuel than modern 4-strokes

Key Specifications

Engine Type: 3-Cylinder, 2-Stroke, Midrange Outboard

Displacement: 1140 cc (69.6 ci)

RPM Range: 4500 – 5500 RPM

Weight: ~261 lbs (119 kg)

Fuel/Oil Mixing: Precision Blend Oil Injection (no need to pre-mix at the tank on most models)

Common Maintenance & Trouble Areas

Carburetors: Because this engine uses carburetors, they frequently need cleaning or rebuilding if the motor has been sitting or running roughly.

Water Pump Impeller: The water pump (and impeller) should be replaced every 1–3 years depending on usage to avoid overheating.

Fuel Contamination: Standard 2-strokes are sensitive to fuel issues. Using a dedicated water-separating fuel filter (like a Racor) is highly recommended

Corrosion: Yamaha outboards can be susceptible to corrosion. It is critical to inspect the exhaust tuner and mounting brackets for salt buildup or deterioration