Unique Products for Your Boat
  • CMI-72-ER - 72A Externally Regulated Marine Alternator

    $389.50 $329.50


    We Do Not Ship Alternators Internationally 

    IMPORTANT: If you are unsure about fitment, or compatibility with LiFePO4 batteries, please use the "Contact Us" tab at the top of this page.

    The CMI-72-ER

    This 72A Leece-Neville / Motorola frame externally regulated small case alternator was specifically built, from the component level, ready to drop into a Universal or Westerbeke diesel with a 3/8" belt. The CMI-72-ER is directly built on the same frame as the original 51A 8MR2049K or 8MR2049KA only with a 72A output. This alternator ready to accept an external regulator such as a Balmar MC-614, ARS-5 or the very affordable Wakespeed WS100.

    What sets this alternator apart from an off the shelf unit are the components chosen to build it and make it ready for installation. High copper content brushes, high output diodes, high volume fan & a D+ terminals just to name a few. We've also added a custom billet machined pulley make this the ideal replacement alternator for a Universal or Westerbeke Diesel engine. The amperage of this unit was specifically chosen to work in concert with the stock 3/8" width v-belts to minimize belt dusting and maximize amperage performance.

    The CMI-72-ER includes a custom billet machined 3/8" belt pulley (not cheap stamped steel), upgraded high-copper content brush assembly, heavy duty diodes in the rectifier, ready for external regulation, D+ terminal as well as an AC Tap for your tachometer. The 2" foot accepts a 3/8" bolt. Please ensure your alternators pivot bolt is 3/8" OD before ordering.

    All of these features are by Compass Marine Inc. so you have a ready to run unit. Even if you were to source the parts and build this alternator yourself you simply can't beat this price.

    External Regulator: 
    Pair this alternator with the Wakespeed WS100 (includes alt and battery temp sensor) for the least expensive externally regulated alternator package on the market at just $622.49. Healthy charging for less than the cost of the stock OEM Universal/Westerbeke alternators with dumb internal regulator.

    CMI-72-ER Specifications:

     This 72A externally regulated alternator is intended to replace the stock alternators found on many Universal Diesel or Westerbeke engines. It will fit any Universal or Westerbeke engine that uses a 2" foot 3/8" bolt bore 8MR style alternator. It will also fit many other applications that use a 2" foot with 3/8" pivot bolt. This alternator fills the gap between a true high performance alternator (see our other alternator offerings) and the very, very expensive/over-priced factory internally regulated alternators. It was designed to meet a price and performance niche not available to boaters previously.


    The CMI-72-ER comes standard with a tachometer output stud (stator tap) for diesels that run the tachometer sense off the alternator. It also has D+ terminal. Not all engines drive the tachometer from the alternator, but most Westerbeke and Universal engines do.

    Special features:

  • Intended to fit Universal & Westerbeke diesels that use an 8MR Leece-Neville with 3/8" Bore Foot
  • Externally Regulated - Ready to pair with a Balmar or Wakespeed Regulator
  • 72A cold rated, with excellent high idle performance
  • 14GA top quality stator magnet wire means better cooling and higher temperature tolerance
  • Epoxy coat finished both inside the case and outside
  • Precision machined rotor and slip rings for greater contact at all RPM.
  • Heavy Duty Diodes
  • High Volume Directional Fan (clockwise rotation - Optional bi-directional fan is available)
  • Billet Machined Pulley - 2.6" Diameter X 3/8" or 10mm Belt (1/2" v-pulley available)
  • Brushes are high copper content not run of the mill cheap carbon brushes
  • Stator Tap for tachometer
  • D+ Terminal
  • 2" Foot With 3/8" Bolt Bore
  • Alternator is Case Grounded
  • Hand assembled/built by Compass Marine, from raw components, in Maine, USA

    *All CMI Alternators are custom built and may require a 1- 2 week lead time.