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Alternator for Cummins Mercruiser EI/ES 165-300 2004-2005 - 12V 65A

Alternator for Cummins Mercruiser EI/ES 165-300 2004-2005 - 12V 65A

SKU:400-46025

Regular price £199.10 GBP
Regular price Sale price £199.10 GBP
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Alternator for Cummins Mercruiser EI/ES 165-300 2004-2005 - 12V 65A

Replaces Mercury Marine 807653 · Lester 12176 · Sierra 18-5967 / 18-5979 / 18-6265

This alternator is built to OEM specifications as a direct fit and function replacement for Cummins Mercruiser inboard and Mercruiser sterndrive engines. It is an IR/EF unit - internally regulated with an external fan - rated at 12 volts and 65 amps.

The unit rotates clockwise (CW) and uses a six-groove (S6) pulley, matching the original factory configuration for a straight bolt-in fit.

Key Features

  • 12-volt, 65-amp output
  • IR/EF design - internally regulated, externally cooled
  • Clockwise (CW) rotation
  • S6 (6-groove) pulley
  • Direct fit for Cummins Mercruiser EI and Mercruiser ES models
  • 12-month warranty as standard

Technical Specs

Specification Detail
Voltage 12V
Amperage 65 Amp
Rotation CW (Clockwise)
Regulator IR (Internally Regulated)
Fan Type EF (External Fan)
Pulley Type S6 (6-Groove)

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
Cummins Mercruiser EI 165, EI 250, EI 300 (inboard) 2004-2005
Mercruiser ES 165, ES 250 (sterndrive) 2004-2005
Mercruiser 454 cu in 7.4L V8 1993-2005

OEM Part Number Cross Reference

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

Part Number Manufacturer / Brand
807653 Mercury Marine
AC155616, AC165617 Mando
18-5967, 18-5979, 18-6265 Sierra
AMN0005 Arrowhead
12176 Lester

Frequently Asked Questions

Will this alternator fit my Mercruiser engine without modification?

Yes. This is a direct OEM-fit replacement built to the same specification (12V, 65A, IR/EF, CW rotation, S6 pulley) as the original unit, so no modification is required.

How do I confirm this is the right unit for my engine?

Compare the number stamped on your existing alternator against the cross reference table above - Mercury Marine 807653, Mando AC155616 / AC165617, Sierra 18-5967 / 18-5979 / 18-6265 or Lester 12176 all indicate this unit.

What's included with this part?

You receive the alternator unit only. Mounting hardware and pulleys are not included unless already fitted to the original unit you are replacing.

How can I tell my old alternator has failed?

Common signs include a warning light staying on, dimming battery-charging performance, a dead or slowly draining battery, or unusual whining noises from the unit.

Why does rotation direction matter?

This unit rotates clockwise (CW). Fitting an alternator with the wrong rotation direction will not charge correctly, so always confirm your original unit's rotation before ordering.

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