Mercury 300L FourStroke DTS Outboard Motor

This used Mercury 300L FourStroke DTS is a 300 hp V8 wired for digital, cable-less throttle and shift, riding on a 20-inch shaft sized for a mid-depth transom. Peak output on the 4.6-liter, 279 cid block arrives somewhere in the 5200-6000 rpm band, with 32 valves spread across a pair of overhead cams.

What the DTS badge means here

Digital Throttle and Shift needs its own control box, sold apart from the powerhead, and hydraulic or power steering is likewise an add-on rather than standard equipment. The 20-inch shaft is set at the factory and cannot be lengthened, so measure your transom before ordering rather than after.

Weight, charging, and upkeep

Mercury lists 527 lbs dry for this motor on a conventional mid-section, fed by a long-runner intake tuned for steady delivery rather than peak rpm. An 85-amp alternator with idle charge keeps batteries up even well below cruise, and the onboard warning system watches for low oil pressure, overheating, and sensor faults the whole time it runs.

Is a propeller included? No, match one to the boat and gearing separately.

Do I need a separate control box? Yes, DTS hardware is purchased apart from this powerhead.

Ask about hours and upkeep history before committing, since this powerhead is sold used, and have the lower unit checked too. Mercury's total coverage runs 5 years here: a 3-year standard term plus 2 added years under the Product Protection Gold plan.