6LY400

The 6LY400 and 6LY440 form Yanmar's 6LY-CR series, which Yanmar calls the fourth generation of its 6LY block. Shown at METS 2015 and in production from early 2016, they keep the 5.813-litre, 106 x 110 mm inline-six of the mechanically injected 6LY2A/6LY3 engines but add Denso common-rail injection, a redesigned 24-valve cylinder head and new manifolds. Both ratings share the same block, 3300 rpm rated speed and 585 kg dry weight; they replaced the 6LY3-UTP/STP/ETP generation and remained Yanmar's most powerful common-rail engines until the 6LF and 6LT arrived in 2020.

They are inboard engines for planing and semi-planing motor yachts, sport-fishing boats and light commercial craft. Yanmar's datasheet lists Kanzaki KMH61A2 (down-angle) and KMH61V2 (V-drive) gears and the ZF280-1 parallel gear, with other ZF gears on request, and the series page also mentions jet drives. Control is electronic through Yanmar's vessel control system (VC10/VC20 today), with the JC20 shaft-drive joystick as an option.

The 6LY400 is the lower of the two ratings.