The Yanmar LHA Series is a compact, turbocharged four-cylinder marine diesel with a long production history and a reputation as a genuine workhorse. Our range covers the two higher ratings in the family: the 4LHA-DTP at 200 mhp and the intercooled 4LHA-STP at 240 mhp, both turbocharged, direct-injection fours rated at 3,300 rpm. The two models share the same four-cylinder block, so the installed footprint is similar across the pair — useful when a repower needs to fit existing engine beds.
What sets the LHA apart today is its mechanical simplicity. These are direct-injection engines with a conventional in-line injection pump and mechanical controls rather than common-rail electronics — a straightforward, well-understood design that is easy to service, tolerant of hard work, and equally at home in recreational boats and light commercial duty. It is one of the reasons the LHA has remained such a popular repower engine for older shaft-drive cruisers and diesel sterndrive boats.
The LHA Series range
Because the 4LHA-DTP and 4LHA-STP share the same four-cylinder block and a similar installed footprint, choosing between them is really a question of how much power your hull needs. The 200 mhp DTP suits lighter or semi-planing hulls and owners chasing an economical cruise, while the intercooled 240 mhp STP is the pick for heavier boats, higher target speeds, or repowers replacing a larger petrol or diesel engine where you don't want to give up performance. Gearbox ratio and propeller selection matter as much as the rating itself, so we work from your hull type, weight and current setup, then confirm the match on a commissioning sea trial.
Drive options
Shaft drive (inboard)
Conventional inboard installations pair the LHA with Yanmar's Kanzaki KMH-series marine gearboxes — a down-angle output as standard, with V-drive versions offered in some markets — while ZF and Twin Disc transmissions were fitted to some models. We match gearbox and ratio to your existing shaft line and propeller.
Sterndrive (Z versions)
Z-spec LHA engines are configured for diesel-rated MerCruiser Bravo sterndrives, a well-documented factory pairing. Drive compatibility and rating need to be confirmed for each boat, particularly on petrol-to-diesel conversions.
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 LHA Series from Mariner
Mechanical, serviceable design
Direct injection with a conventional in-line pump and mechanical controls — no common-rail electronics. The LHA is a simple, robust engine that is straightforward to maintain and diagnose, which is exactly what many owners want in a repower.
A proven repower workhorse
With decades of service worldwide in cruisers, fishing boats and light commercial craft, the LHA has a well-earned reputation for durability. Its compact four-cylinder package makes it a practical fit for many older shaft-drive and diesel sterndrive hulls.
Authorised dealer support in Melbourne
Mariner Engineering is an authorised Yanmar dealer based in Spotswood. We handle the full job — engine supply, repower engineering, installation, sea-trial commissioning — and back it with factory-trained servicing and genuine Yanmar parts on Port Phillip Bay.
Yanmar LHA Series — your questions answered
Which LHA model do I need for my boat?
It comes down to hull weight, hull form and the cruise speed you're after. As a rule of thumb, the 200 mhp 4LHA-DTP suits lighter hulls and moderate cruising speeds, while the 240 mhp 4LHA-STP is better for heavier boats or owners who want stronger performance in reserve. Send us your boat details — make, length, weight, current engine — and we'll recommend a model, gearbox ratio and propeller, then verify it on the water.
Will an LHA fit as a repower in my existing shaft-drive boat?
Often, yes — the LHA's compact four-cylinder package is one of the reasons it's such a common repower choice. We check engine bed dimensions and mounts, shaft size and gearbox ratio, cooling, exhaust and fuel systems before quoting, and our changeover packages cover removal of the old engine, installation, and sea-trial commissioning.
Can an LHA replace the engine in my sterndrive boat?
Z-spec versions of the LHA were factory-configured for diesel-rated MerCruiser Bravo sterndrives, so diesel sterndrive repowers are well proven. If your boat currently runs a petrol engine, the existing drive may not be rated for diesel torque and might need upgrading or replacing — we assess the whole package, not just the engine, before recommending a path.
Is the LHA's mechanical injection a drawback compared with newer common-rail engines?
It's a trade-off, and an honest one. Common-rail engines are quieter and more refined, but the LHA's mechanical direct injection means fewer electronic components, simpler diagnostics and servicing that any competent diesel mechanic can understand. For working boats and owners who value simplicity, that's a genuine advantage. Either way, we service what we sell with factory-trained technicians and genuine Yanmar parts.
Ask about the LHA 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 LHA Series model and drive, with pricing, usually within 1 business day.