Saltwater is the hardest environment a turbocharger will ever live in. Boost Lab, Inc. rebuilds marine diesel turbos for Yanmar sailboat and sportfish engines, Volvo Penta KAD and D-series sterndrives and inboards, Cummins marine B and C-series power, John Deere marine PowerTech, and Detroit Series 60 marine. Sportfish, trawlers, sailboats, workboats: pull the unit, ship it in, and get back on the water.
From 30 hp sailboat auxiliaries to 800 hp sportfish power, the turbo families repeat. Find yours.
Yanmar's sailboat and light-cruiser diesels run compact MHI and IHI turbos that live inches from a raw-water exhaust mixing elbow. When the elbow clogs or corrodes through, exhaust backpressure and water intrusion take the turbo with it. We rebuild the turbo; make sure the elbow gets replaced or you will see us twice.
The compressor-plus-turbo KAD series is a masterpiece with a maintenance appetite. The turbos are KKK/BorgWarner and Garrett units under Volvo part numbers, and complete assemblies from Volvo cost eye-watering money when available at all. Rebuilding the original is the sane path on these engines.
The TAMD workhorses and modern D4/D6 common-rail engines power everything from trawlers to pilot boats. Holset, Garrett and BorgWarner units by application. High-hour commercial engines respond especially well to scheduled turbo rebuilds rather than run-to-failure.
The 6BTA and 6CTA dominate sportfish and trawler repowers, running Holset H1C/HX35/HX40-family turbos with marine-specific housings. Cores are plentiful, corrosion is the enemy, and our Holset bench experience runs deep. QSB and QSC electronic engines follow the same pattern with later Holset hardware.
Deere's marine PowerTech engines power workboats, gensets and displacement cruisers with Schwitzer S2BW-family turbos under RE-prefix numbers like RE502857. Same tough hardware as the ag units, plus marine corrosion. Fully rebuildable.
Series 60 marine conversions run Garrett units like the UTW7801, and Cat 3126/C7/C12/C18 marine engines carry familiar heavy-truck-family turbos in marine trim. If it is on a boat and it spins, we can likely rebuild it; send the tag photos through the form.
On raw-water-cooled marine diesels, the number one turbo killer is not the turbo. Cast iron and mild steel exhaust mixing elbows corrode from the inside out where you cannot see it, restricting flow with carbon and scale, then finally letting water run backward toward the turbine. A rebuilt turbo installed against a rotten elbow is a wasted rebuild. Inspect or replace the elbow with every turbo job, and consider a 316 stainless elbow where available. We flag elbow-related damage on every marine assessment so you know the root cause.
Verified Yanmar, Volvo Penta, Cummins and Deere marine numbers. Marine turbos are tag- and plate-specific: confirm your engine plate before ordering anything. Search by any number.
| Turbo PN | Model | OEM PN | Application | Notes |
|---|---|---|---|---|
| IHI VA190016 (MYCZ) | IHI RHB52YW | Yanmar 129671-18001 | Yanmar 4JH3-T / 4JH3-TE | Sailboat auxiliary workhorse |
| IHI VA190052 (MYER) | IHI RHB52YW | Yanmar 129671-18010 | Yanmar 4JH4-TE | Later 4JH service number |
| IHI VA190017 (MYCY) | IHI RHB52YW | Yanmar 129672-18001 | Yanmar 4JH3-HTE | High-output 4JH variant |
| IHI VB720033 (MYBH) | IHI RHE62W | Yanmar 119775-18010 / -18011 | Yanmar 6LP-STE, 6LP-DTE, 6LP-DTZE | Toyota-based 6LP V6 diesel |
| Tag-specific | IHI RH-series | Yanmar 119773-18010 | Yanmar 4LHA series | Companion stainless elbow: 119773-13501 |
| 53269886497 / 53269706497 | KKK/BorgWarner K26 | Volvo 861260, 3802070, 838697, 860916 | Volvo Penta TAMD41, AQAD41A, AD41P, KAD42, TAMD31/AD31 | The classic 41-series/KAD42 K26 |
| 53269886750 / 53269886752 | KKK/BorgWarner K26 | Volvo 3581012 | Volvo Penta KAD44, KAMD44 | Compressor-plus-turbo compound engines |
| 53269886751 / 53269706751 | KKK/BorgWarner K26 | Volvo 3581755, 3802105 | Volvo Penta KAMD44P, KAD44-3 | Late 44-series calibration |
| 53269887200 / 53269707200 | KKK/BorgWarner K26 | Volvo 3802125, 3583006 | Volvo Penta KAD43 / KAD300 family | Sources vary on 43 vs 300; verify engine plate |
| Holset 3536621H / 3536620 | Holset HX40M | Cummins 3802829 | Cummins 6BTA 5.9 marine | Sportfish repower standard |
| Holset 3538453H / 3538452 | Holset HX35 | Cummins 3802915 | Cummins 6BTM / 6BT marine 260 hp | Marine wastegated HX35 |
| Holset 3534378H | Holset H1E | Cummins marine channel | Cummins 6BTA 5.9 marine | Earlier H1E-equipped ratings |
| Holset 3538723 | Holset H1C | Cummins 3802870 | Cummins 4BT / 6BT marine | Small-frame early marine unit |
| Holset 4035782H | Holset HX40 | Cummins QSB marine channel | Cummins 6B / QSB 5.9 marine | Electronic QSB-era hardware |
| Holset 3535635 / 3535636 | Holset HX40W | Cummins 3802651 | Cummins 6CT / 6CTA 8.3 (incl. marine ratings) | 8.3L trawler and sportfish power |
| Schwitzer 170259, 12749880059 | S2BW | Deere RE502857, SE502177 | Deere 4045TFM / 6068TFM marine PowerTech | Same family as Deere ag units |
| UTW7801 (Garrett) | Garrett | Detroit marine channel | Detroit Series 60 marine | Marine-rated Series 60 unit |
| Tag-specific | Cat marine by rating | Verify by serial | Cat 3126 / C7 / C12 / C18 marine | Serial-number-specific configurations |
Salt, heat, and low hours between long idle periods: the marine failure patterns are unlike anything on the road.
The signature marine killer. A corroded or clogged mixing elbow lets raw water siphon or surge backward into the turbine housing. Salt attacks the wheel and shaft, and if water reaches the cylinders the engine is next. Turbine-side rust on a marine core is the fingerprint; we always report it because the elbow, not the turbo, is the root cause.
Even without ingestion, the salt air of an engine room corrodes actuator rods, clamps, fittings, and water-cooled housing passages. Seized wastegate hardware and crumbling coolant fittings are routine on cores from coastal boats. We replace corroded external hardware as part of the rebuild.
Sailboat auxiliaries and trawlers that never see full load soot up their turbines and elbows. The turbo never reaches self-cleaning temperature, deposits build, and boost fades. After the rebuild, run the engine hard periodically; marine diesels want load.
Run in on plane, tie up, shut down. The heat soak with no idle-down cokes the oil in the center section exactly like a farm tractor. Three to five minutes of idle before shutdown is the cheapest turbo insurance a boat owner can buy.
Water-cooled turbo and manifold passages scale up with salt and mineral deposits, insulating the very parts the water is meant to cool. Local overheating warps housings and cooks seals. Rebuilds include descaling water passages where the design allows.
Boats sit. Months of humidity inside a salt-loaded exhaust system corrode the turbine shaft right at the seal, and the first start of the season grinds the rust through the bearings. If your boat winters ashore, fogging the engine and sealing the exhaust makes the spring survey kinder.
Very much so. KAD-series turbos are conventional KKK/BorgWarner and Garrett hardware under Volvo part numbers, and rebuilding your original costs a fraction of a dealer assembly, when the assembly is even available. Volvo hardware in serviceable condition rebuilds routinely.
Often both, and the elbow usually started it. A clogged or corroded mixing elbow chokes the exhaust and can push water toward the turbine. Send the turbo in for assessment and inspect the elbow while it is off; if the elbow is original and more than a few seasons old, replace it.
Constantly, and we report it honestly because it changes the fix. Turbine-side rust means water came backward through the exhaust, and installing a rebuilt turbo without fixing the elbow or anti-siphon setup guarantees a repeat failure.
Yes. Workboats, charter boats, and commercial fishing vessels are welcome, and our dealer program serves boatyards and marine mechanics with wholesale pricing and priority turnaround. Email sales@theboostlab.com.
On commercial and heavily used engines, yes. A scheduled rebuild during the off season beats a failure offshore, and marine turbo failures have a way of cascading into water ingestion events. If shaft play is measurable at survey time, that is the moment.
Start at repair.theboostlab.com. Drain oil and water passages completely, cap all openings, and double-box with solid packing. Ship to Boost Lab, Inc., 37833 Pineapple Ave, Unit A, Dade City, FL 33523. We serve boat owners nationwide.