Yanmar Marine Remap Dorset | 6BY2 4BY2 4JH Tuning

Yanmar diesel inboards are among the most trusted marine engines on the South Coast, fitted to RIBs, sportscruisers and displacement yachts from Poole Harbour to Southampton Water. Factory calibration is deliberately conservative, favouring emissions compliance and longevity over usable acceleration. 24Tuning delivers custom Stage 1 ECU remapping for 6BY2, 4BY2 and 4JH platforms — mobile to your marina, boatyard or private mooring.

Why Remap a Yanmar Diesel?

Yanmar's global emissions and warranty limits leave torque and throttle response on the table, particularly noticeable at planing speed and under load. A Stage 1 remap recalibrates fuelling, boost and torque request maps within the engine's mechanical envelope.

Stronger acceleration onto the plane
Improved mid-range torque under load
Sharper throttle response at the helm
No hardware changes required for Stage 1
Fully reversible with original map restore

Yanmar Engines We Cover

We cover common-rail and mechanical Yanmar marine diesels including:

6BY2 Series (High-Output V6)

6BY2-260
6BY2-220

4BY2 Series

4BY2-180
4BY2-150

4JH Common Rail & Mechanical

4JH110
4JH80
4JH80-C
4JH4-TE
4JH4-TCE
4JH4-HTE
4JH3-DTE

Estimated Stage 1 Gains

Engine / Model	Stock	Stage 1 (est.)	Gain	Notes
6BY2-260	259 HP	~282 HP	+~23 HP	Stage 1 software
6BY2-220	220 HP	~240 HP	+~20 HP	Stage 1 software
4BY2-180	180 HP	~196 HP	+~16 HP	Stage 1 software
4BY2-150	150 HP	~163 HP	+~13 HP	Stage 1 software
4JH110	110 HP	~120 HP	+~10 HP	Stage 1 software
4JH80	80 HP	~87 HP	+~7 HP	Stage 1 software

Figures are conservative estimates based on typical Stage 1 marine calibrations. Exact gains depend on engine condition, propeller, load and use case. Torque figures of 0 Nm from source databases are omitted.

Alientech KESS3 marine tuning tool connected to a Yanmar diesel ECU on a Dorset boat — Alientech KESS3 bench and boot tooling used for Yanmar 6BY2 / 4BY2 / 4JH calibration.

Mobile Marina Process

We come to your marina, slipway, dry stack or private berth across Poole Harbour, Bournemouth, Southampton Water, Lymington, Hamble and the wider Dorset & Hampshire coast.

Quote & compatibility — share engine model, year and ECU details
£50 booking deposit — confirm berth access and tide window
On-site diagnostics — full health check before any write
Factory map backup — secure original file for full reversion
Custom Stage 1 calibration — in-house map for your use case
Sea trial verification — where conditions allow

Book Mobile Service ECU Testing & Repairs

What You’ll Notice on the Water

Faster, more confident acceleration onto the plane
Stronger low-down pull when loaded or towing a tender
Sharper throttle response for harbour manoeuvring
Custom map matched to prop, gearing and vessel weight

Key Benefits

Custom 6BY2/4BY2/4JH Maps
Mobile Marina Visits
Factory ECU Backup
Lifetime Software Warranty
Common Rail & Mechanical Coverage
Sea Trial Verification
Poole & Southampton Coast
Diagnostics Included

Pricing

Yanmar Stage 1 remapping from £799 including diagnostics, factory backup, custom calibration and on-board installation. Larger 6BY2 commercial installs are quoted individually. Secure with a £50 deposit via online booking.

Related Services

Volvo Penta Remap — D6 / D4 / D13 diesels
Hyundai SeasAll Remap — S / L / H series
Marine & Boat Remap — full boat overview
ECU Testing & Repairs — faulty marine ECUs
Southampton coverage — Southampton Water visits

Frequently Asked Questions

Which Yanmar ECUs can you remap?

We cover common-rail 6BY2 and 4BY2 platforms plus mechanical and common-rail 4JH variants. Confirm your exact engine code and year when booking so we can verify tooling compatibility.

Do you work on-board at the marina?

Yes. Our mobile marine engineers attend marinas, moorings and boatyards across Poole Harbour, Bournemouth, Southampton, Lymington and Hamble.

Is Stage 1 safe for a Yanmar in regular sea use?

Yes when the engine is healthy. We run diagnostics first, stay within mechanical limits, and keep a full factory map backup so the engine can be reverted at any time.

How much gain can I expect from a 4JH?

Typical 4JH Stage 1 gains are modest but noticeable, around 8-10% depending on model and condition, focused on throttle response and mid-range pull rather than headline horsepower.

Yanmar Remapping on the Dorset & Hampshire Coast

Yanmar 6BY2, 4BY2 and 4JH diesels power a huge share of the RIBs and sportscruisers moored across Poole Harbour and Southampton Water. 24Tuning provides mobile Stage 1 calibration with Alientech / Autotuner tooling, factory backup and lifetime software warranty.

Book a marina visit or send your engine details for a confirmed quote.

Yanmar Marine Diesel Remap