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Alternator for Mercury & Mariner Outboard 225 250 300 ProMax 1994-2000 - 12V 50A

Alternator for Mercury & Mariner Outboard 225 250 300 ProMax 1994-2000 - 12V 50A

SKU:400-52198

Regular price £175.20 GBP
Regular price Sale price £175.20 GBP
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Alternator for Mercury & Mariner Outboard Engines

Fits Mercury 225, 250 and 300 ProMax Racing Outboards, 1994-2000 · 12V 50 Amp

This alternator is a direct replacement for the original 50-amp unit fitted to Mercury Marine and Mariner outboard engines built around the 3.0L / 185ci V6 powerhead. It is manufactured to OEM specifications for fit, form and function, so it installs in place of the original part without modification.

The unit is rated 12 volt, 50 amp with clockwise rotation, an internal regulator (IR) set at the 3 o'clock position and an internal fan (IF). It uses a single-groove solid pulley of 63mm outside diameter, a 100mm OD stator and an M6-1.0 B terminal on a negative-earth system, and pairs with rotor part number 021200-5651. Note that the mounting differs from some earlier Mercury alternators, so please confirm against your original unit before ordering.

Key Features

  • 12-volt, 50-amp output
  • Clockwise (CW) rotation
  • Internal regulator (IR) at 3 o'clock, internal fan (IF)
  • 1-groove solid pulley, 63mm OD
  • 100mm OD stator, negative earth
  • Pairs with rotor #021200-5651

Technical Specs

Specification Detail
Voltage 12V
Amperage 50A
Rotation CW (clockwise)
Pulley 1-groove solid, 63mm OD
Regulator Type IR (internal), 3 o'clock position
Fan Type IF (internal)
Stator OD 100mm
B Terminal M6-1.0
Polarity Negative earth
Weight 3.43 kg
Rotor Reference 021200-5651

Vehicle Fitment Guide

Years shown are the overall coverage span for this part. Please confirm against the OEM part number on your original unit before ordering.

Make & Model Years
Mercury Marine 225L, 225XL, 225XXL, 225CXL, 225CXXL (3.0L) 1994-1999
Mercury Marine 225XL EFI, 225XXL EFI, 225CXL EFI, 225CXXL EFI 1995-2000
Mercury Marine 225L EFI 1996-2000
Mercury Marine 225CXL Seapro 1996-1998
Mercury Marine 250XL EFI, 250XXL EFI, 250CXL EFI, 250CXXL EFI 1995-2000
Mercury Marine 300L, 300XL, 300CL, 300CXL ProMax Racing 1998-2000
Mariner Marine 225 Carb, 225 EFI, 225 Sea Pro, 250 EFI (GM 3.0L) Not specified

OEM Part Number Cross Reference

Aftermarket replacement. OEM part numbers are listed for reference only.

Part Number Manufacturer / Brand
821663, 821663-1, 821663A1, 821663-A1 Mercury Marine
101211-8580 Denso
12358N WAI

Frequently Asked Questions

Will this fit my Mercury Marine outboard without modification?

Provided your original alternator matches the mounting pattern described above (this unit's mounting differs from the earlier 495277 equivalent), this is a direct OEM-spec fit.

What's included?

The alternator unit only.

How can I tell my alternator has failed?

Signs include a charge warning light, a battery that will not hold charge, dimming lights, or unusual noise from the unit.

Does it suit the 300 ProMax Racing powerhead?

Yes — the 1998-2000 300L, 300XL, 300CL and 300CXL ProMax Racing outboards use this same 50-amp charging unit.

What rotor does this alternator use?

Rotor part number 021200-5651.

Dispatched from the UK · 12-month warranty · Fitment support from our technical team
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Shipping calculated at checkout. Free shipping over £150. Terms apply