The 6LY-CR is the fourth generation of Yanmar's long-running 6LY line, a classic that dates back to 1989: an in-line six-cylinder, 5.81-litre marine diesel offered in two ratings — the 6LY400 at 400 MHP and the 6LY440 at 440 MHP. Where earlier 6LYs used mechanical injection, the CR generation runs a Denso common rail fuel system with a 24-valve cylinder head and a water-cooled turbocharger, so it starts cleaner, runs quieter and pulls harder through the mid-range while meeting current recreational emissions standards.
Its defining trait is power density in a compact package. The purpose-built marine block keeps the engine tight and relatively light for its output, which is why the 6LY-CR turns up in twin-engine rooms under flybridge cruisers and sportfishers where physically larger 400-plus-horsepower diesels are a squeeze. That same footprint makes it one of the more practical repower options for boats built around earlier 6LY2 and 6LYA engines.
The 6LY-CR Series range
Both models share the same 5.81-litre block, common rail system and gearbox options — the choice is purely about rating. The 6LY440 suits heavier hulls, higher target cruise speeds and twin installations where you want throttle headroom; the 6LY400 is the pick where the hull needs less power or spends long hours at cruise and benefits from a more relaxed duty point. The right answer comes from your boat's weight, hull type and how you actually run it — we work through that with you, match the gear ratio and propeller, and confirm performance on a commissioning sea trial.
Drive options
Shaft drive — down-angle
Kanzaki KMH61A2 8-degree down-angle gearbox, the common choice for direct shaft installations in planing cruisers and sportfishers.
Shaft drive — V-drive
Kanzaki KMH61V2 12-degree V-drive gearbox for aft-engine layouts where the engine sits back over the shaft line, freeing up accommodation space.
Shaft drive — parallel (ZF)
ZF280-1 parallel-shaft gearbox for conventional in-line shaft installations, with a range of reduction ratios to suit the hull and propeller.
Boats this family suits
Pricing, repower advice or a spec for your boat
Tell us your vessel and how you use it — we'll recommend the right model and drive, with dealer pricing.
Why buy your 6LY-CR Series from Mariner
Common rail, fourth-generation refinement
Denso common rail injection, a 24-valve head and a water-cooled turbo give the 6LY-CR cleaner combustion, quieter running and sharper throttle response than the mechanical 6LYs it replaced.
Built for tight engine rooms and repowers
A compact package for 400–440 MHP means the 6LY-CR fits spaces many rivals can't — including hulls originally built around earlier 6LY generations.
Authorised Yanmar dealer support in Melbourne
Mariner Engineering supplies, installs and sea-trial commissions the 6LY-CR from Spotswood, with factory-trained technicians and genuine Yanmar parts.
Yanmar 6LY-CR Series — your questions answered
How do I choose between the 6LY400 and 6LY440?
They're the same engine at different ratings, so it comes down to your hull and how you use it. Heavier boats, higher cruise-speed targets and twin installs that need reserve favour the 6LY440; lighter hulls and long steady cruising often suit the 6LY400. Bring us your boat's displacement, hull type and current performance figures and we'll run the numbers before you commit.
Is the 6LY-CR a good repower for an older 6LY2 or 6LYA?
Often, yes — the CR generation stays compact enough to fit many engine rooms built around earlier 6LYs. It's still not a straight drop-in: mounts, gearbox ratio, shaft size, exhaust and propeller all need checking, and the extra power can change prop requirements. We handle the full changeover, including engineering checks, installation and sea-trial commissioning.
Can I get a 6LY-CR with a saildrive or sterndrive?
No — the 6LY-CR is shaft-drive only, offered with 8-degree down-angle (KMH61A2), 12-degree V-drive (KMH61V2) and parallel (ZF280-1) gearbox options. If you want a sterndrive at this end of the range, Yanmar's 8LV V8 is offered with one; saildrives sit with the smaller JH family and its SD60 leg. We can advise on the right fit for your boat.
Who services the 6LY-CR in Melbourne?
We do. Mariner Engineering is an authorised Yanmar dealer at Spotswood with factory-trained technicians, genuine parts and the diagnostic tooling the common rail system requires. We service the whole 6LY line — current CR engines and earlier generations — for boats across Port Phillip Bay and Victoria.
Ask about the 6LY-CR Series range
Tell us your vessel, how you use it, and whether this is a new build or a repower — our team will recommend the right Yanmar 6LY-CR Series model and drive, with pricing, usually within 1 business day.