Mercury 90ELPT Command Thrust FourStroke

This used Mercury 90ELPT Command Thrust FourStroke is a 90 hp, four-cylinder outboard on a 20 inch shaft, built around the Command Thrust gearcase for added low-speed pushing power on a heavier hull.

What to check before buying

Mechanical throttle and shift hardware is not included and must be bought separately; steering can run dual-cable mechanical, hydraulic power steering, or convert to an advanced tiller. The shaft here is 20 inches, so measure your transom.

Specifications worth knowing

This four-cylinder, 2.1 liter powerhead runs electronic fuel injection with a single overhead cam. The Command Thrust gearcase is geared 2.38:1, and full throttle tops out between 5000 and 5800 rpm. At the dock it weighs 363 lbs dry, and the water-cooled alternator is rated for 35 amps (441 watts). Shallow water trim is rated at 20 degrees, with a maximum trim range of 22 degrees and a maximum tilt range of 70 degrees.

What comes with it

SmartCraft Engine Guardian watches the engine during operation, starting is Smart Start electric, and the crankcase holds 5.5 quarts of oil. A propeller is not included, so plan to source one separately for your boat.

Common questions

Will I need to buy a propeller too? Yes, a propeller is not included with this motor.

What minimum fuel grade does it need? 87 octane unleaded regular at minimum, per Mercury's guidance.

What recommended oil does Mercury list? NMMA certified FCW SAE 10W-30.