Marine engines Reconditioning guides by engine family
The marine engines we see most often, from boats worldwide. Each guide covers specifications, documented faults, the reconditioning process and prices - based on manufacturer datasheets, service manuals and 30+ years of workshop experience.
Choose an engine family
Click an engine to see specifications, common faults, the reconditioning process and prices.
Volvo Penta D2-55
The standard choice in 35-45 ft cruising sailboats since 2001. Built on the Shibaura N844L block via the Perkins-Shibaura JV. Naturally aspirated, in-line Bosch pump, no common rail. Complete guide with torque specs and failure modes.
Open guideVolvo Penta D4-300
Volvo Penta's top-end unit for planing motorboats 35-50 ft. Compound charging (supercharger + turbo) with an intercooler, DOHC and common rail. More power but pricier servicing. Guide covering common faults, copper-sleeve failure and the inspection routine.
Open guideVolvo Penta MD22
The direct predecessor to the D2 series. Mechanical Bosch in-line pump, direct injection, MD22L naturally aspirated and MD22P turbo. A classic reconditioning candidate in thousands of Nordic 1990s cruising sailboats.
Open guideVolvo Penta AQ-serien
The whole AQ family of petrol-powered sterndrive engines (AQ131, AQ140A, AQ145, AQ151, AQ171) - marinised Volvo redblocks from the B21 to the 16-valve AQ171. Factory-verified torque figures (TP-30170), drive corrosion and carburettors in one combined guide.
Open guideVolvo Penta TAMD41
A six-cylinder, industrially derived turbodiesel in thousands of Nordic motorboats 30-40 ft. Robust block design - most TAMD41s reach 5 000+ running hours with proper maintenance. No 230 hp variant exists.
Open guideYanmar 4JH4-TE
Yanmar's best-seller in the 40-50 ft segment during its production run. Direct injection with a Bosch VE mechanical distributor pump - not common rail. The aluminium exhaust manifold is the classic weak point.
Open guideYanmar 3GM30F
The classic three-cylinder that powered a whole generation of Scandinavian sailboats. Few components and readily available spares make a full rebuild realistic. Mixing-elbow corrosion is the documented cause of death.
Open guideMercruiser 5.7L MPI
A marine version of the Chevrolet small block 350. The MPI version was introduced in 2001 and was discontinued around 2022-2023 when GM stopped supplying the small-block to Mercury. Aftermarket blocks (DART and others) remain available.
Open guidePerkins 4.108
One of the most reliable post-war marine diesels. Cast-iron block, CAV/Delphi DPA rotary distributor pump, naturally aspirated. Reconditioned with standard processes and good for another 20-30 years.
Open guideBukh DV24 / DV36
A Danish design developed for SOLAS-approved lifeboats. Bukh has built marine engines since 1899. Direct injection, mechanical Bosch pump. Both are still in production under the name DV24/DV36 RME.
Open guideVolvo Penta MD2020
A small three-cylinder sailboat diesel on a Shibaura block, marinised by Volvo Penta. Naturally aspirated, indirect injection, mechanical Bosch pump. Factory-verified torque figures and cylinder head reconditioning. Note: the MD2020 is a 3-cylinder (the MD2010 is a twin).
Open guideVolvo Penta MD2030
A three-cylinder 0.95-litre sailboat diesel from the MD2010-2040 series. Shibaura block, naturally aspirated and indirect injection. Common in 30 ft cruising sailboats. Factory-verified torque figures and cylinder head reconditioning.
Open guideVolvo Penta MD2040
The top model in the MD2010-2040 series: a three-cylinder 1.5-litre sailboat diesel of about 40 hp. According to the factory technical data it is a 3-cylinder (not a 4). Factory-verified torque figures and cylinder head reconditioning.
Open guideVolvo Penta D3
Volvo Penta's five-cylinder common-rail turbodiesel, based on a VM Motori block. DOHC, modern diesel technology in both shaft and sterndrive versions. Factory-verified torque figures, angle-tightened head bolts and injection.
Open guideYanmar 1GM10
Yanmar's single-cylinder 9 hp sailboat diesel from the classic GM series. Raw-water cooled, mechanical injection, extremely simple and dependable. Factory-verified torque figures (kgm converted to Nm) and cylinder head reconditioning.
Open guideYanmar 2GM20
A two-cylinder 18 hp sailboat diesel from Yanmar's GM series, a sibling of the 1GM10 and 3GM30F. One of the most widespread sailboat diesels. Factory-verified torque figures and cylinder head reconditioning.
Open guideMerCruiser 3.0L
The best-selling sterndrive engine of all time - a marine GM 3.0L inline four with the Alpha One drive. Cast-iron block, simple and cheap to recondition. Factory-verified torque figures and cylinder head reconditioning.
Open guideWhat we do with your marine engine
Salt water, high torque and long running hours wear these engines hard. Here are the services we perform most often on marine engines.
Complete engine reconditioning
Inboard, sail-drive and z-drive. Diesel and petrol.
Cylinder head reconditioning
Resurfacing, valve work and pressure testing for salt-water-exposed cylinder heads.
Cylinder head pressure testing
Finds micro-cracks that let coolant into the oil.
Cylinder boring
Berco boring machine, honing to spec. Wet liners and dry sleeves.
Cylinder head resurfacing
Block and head. Corrects distortion from overheating.
Crankshaft reconditioning
Grinding, polishing, balancing. Large marine-diesel crankshafts.
Turbo reconditioning
Volvo Penta D4, Yanmar 4JH, Mercruiser turbo and more.
Our machine shop
Machines sized for marine blocks and crankshaft lengths.
Do you have a marine engine that needs looking at?
Call us or send a quote request and we will review the engine's condition and propose the scope of work. Reply within 24 hours. Quote after inspection.