4.5L 200

The 4.5L 200 is the lower rating of the 4.5-litre V6 Mercury designed and built for marine use rather than marinised from a GM truck block. It is a 275 cu in (4.5 L) 2-valve pushrod V6 with multi-point injection, running the same architecture as the 250 hp H.O. but on a milder calibration whose wide-open-throttle band is 4400–4800 rpm. Mercury launched the 4.5L family at 250 hp in 2014; this 200 hp tune followed for the 2015 model year and is the replacement for the last GM-based 4.3L V6 MPI.

On the current catalog the 4.5L 200 is an Alpha One sterndrive only. It is not listed with Bravo One/Two/Three or the Bravo Four S (the Four S band starts at 250 hp), and there is no 4.5L Horizon or TowSport inboard in Mercury's 2022–2026 recreational lineup. The 200 and 250 share the block; they are not averaged and they are not the old 4.3L.