Mercury 300HP XL FourStroke Outboard

The Mercury 300HP XL FourStroke Outboard carries a 25 inch X-long shaft and remote mechanical steering, longer than the shortest option Mercury also builds in this 300 horsepower range.

Fit

A 25 inch shaft suits a deeper transom than Mercury's shorter options in this lineup; measure carefully, since a V8 this size is costly to re-rig if the shaft length is wrong. Remote mechanical steering means the controls mount to a console with cables, not a tiller.

Powerhead

Electric start and electronic fuel injection power this V8, which comes in at 527 lbs on the scale. Power trim and tilt is standard, sparing you from muscling a motor this heavy up and down by hand.

Included and warranty

Expect mounting hardware, a tool kit, and printed documentation in the box, with Mercury's 3-year warranty attached. Order the propeller separately, matched to your boat and whatever load you usually run.

Mounting notes

Transom bolts, bracing, and overall hull condition matter more on a V8 this size than on a smaller outboard, so have them checked before installation, particularly on an older boat.

How does XL differ from the shorter option in this range? Mainly shaft length: XL runs the 25 inch X-long shaft. Is a propeller included? No.

Running in

Follow Mercury's break-in schedule for the first several hours on a V8 this size, varying throttle rather than holding one speed, to help rings and bearings seat properly.