Mercury 300CXL FourStroke DTS Outboard Motor

The Mercury 300CXL FourStroke DTS is a used 300 horsepower V8 outboard on a 25 inch shaft, built around a high-displacement, quad-cam powerhead for strong torque in the mid-range rather than only at the top of the rev band.

Controls

DTS stands for digital throttle and shift, but that hardware is sold separately from the engine, so confirm you have or are budgeting for a compatible DTS helm before ordering. Steering is hydraulic or power, both optional and likewise not bundled with this engine.

Powerhead and numbers

This V8 spans 4.6 liters (279 CID) in a 64 degree, dual overhead cam, 32-valve layout; bore is 3.6 inches, stroke 3.4 inches, and full throttle spins 5200 to 6000 rpm. Gearcase ratio is 1.75:1, and the alternator puts out 85 amps (1071 watts) with idle charge, and dry weight is 527 lbs. At the extremes, trim covers 20 degrees (-6 to 14) and tilt covers 73 degrees (-6 to 67). Fuel injection is computer controlled with Advanced Range Optimization for cruise-speed economy.

Fuel, oil, and coverage

Mercury calls for 87 octane unleaded regular as the floor, or 90 RON fuel carrying up to 10 percent ethanol, alongside NMMA certified FCW SAE 25W-40 oil, with 10W-30 optional in cold conditions, at a 7 quart capacity. Being used, inspect it with that history in mind. Coverage reaches 5 years overall, built from a 3-year factory term and a 2-year Product Protection Gold extension on top. The propeller is not included.