2019 Mercury 125 HP 4-Stroke 25″ Shaft

Listed as used and described by the seller as like new, this 2019 Mercury 125 HP outboard is a four-stroke engine with a 25-inch shaft and 161 hours of use recorded. It fits boats built for a taller transom, such as larger pontoons or offshore-style console boats that call for a 25-inch shaft rather than the shorter lengths common on smaller runabouts.

How it's set up

The seller notes the engine as serviced and ready to install, complete with its own DTS rigging and gauges. Electric start and power trim come standard, and it is wired as a remote-steer unit rather than a tiller handle. Being a four-stroke, it also skips the premix routine two-stroke owners are used to, since lubricating oil stays in its own internal reservoir instead of being blended into the fuel.

What to check before buying

Measure transom height against the 25-inch shaft before ordering, since a shaft that is too long or short changes where the propeller sits relative to the waterline. Ask about the upkeep behind the 161 recorded hours, including when the water pump impeller and gear lubricant were last serviced, since this is a used rather than new engine. Boaters replacing an older two-stroke of similar horsepower on the same hull should confirm the included DTS rigging and gauge set lines up with what is already installed on the dash.

Will my existing control box work with this engine? Check that the gauges and rigging bundled with this motor line up with your current setup before swapping from a different model.

Why is there no premix step with this one? It runs as a four-stroke, so oil stays in an internal sump rather than being blended into the fuel tank.