Unique Products for Your Boat
  • **SALE** CMI-90-ERM - 90A Motorola Replacment Externally Regulated Alternator

    $368.00 $299.99
    Please enter your alternator belt width and engine brand and model number.


    I Do Not Ship Alternators Internationally

    IMPORTANT:  CMI Alternators are hand built and may require a 1-2 week lead time.

    The CMI-90-ERM: 

    For the first time ever we are offering a sub $300.00 externally regulated alternator! In order to bring better value to our readers & customers we are using custom castings/frames designed as a drop in replacement for the very common Motorola/Leece-Neville/Prestolite 8MR frame alternators. This frame with the 2" "fit kit" (standard) will also replace a 2" foot Delco 10SI or 12SI alternator. Because we can share internal components from this 8MR type frame, on other alternator frames, we can save on manufacturing costs by buying in bulk.  This savings is passed onto you.

    We start with the finest custom, aftermarket & OEM parts we can source & then build these from the ground up as a better & more cost effective alternative to the stock Leece-Neville/Motorola internally regulated alternators. You will not find a better price, or quality externally regulated entry level alternator anywhere.

    WARNING: In order to keep costs down these alternators are for use on DIESEL ENGINES ONLY. They are not spark protected as is required for a gasoline engine.

    External Regulator:  If you select the drop down menu you will see that we can package this alternator with a Balmar MC-614H or ARS-5H regulator, or with these regulators and a temp sensor. We recommend setting the Belt Manager feature to level three to five when setting up the regulator. This alternator is capable of 110A of output when cold and a 1/2" or 3/8" belt can not handle that. We strongly recommend using a temp sensor and Balmar regulators with this alternator. This alternator can be converted to a Balmar / AltMount J10 serpentine pulley on special request.

    We also offer the Sterling ProReg-D external voltage regulator. This regulator is a value regulator and does not offer any way to limit alternator output in order to pair it with your belt. While the ProReg-D is less money, the Balmar regulators are a better match for the CMI-90-ERM.

    CMI-90-ERM Specifications:This is not a cheaply built run of the mill automotive grade alternator with a dumb internal regulator. This is a direct drop in for the very common Leece-Neville 8MR series or a Delco 10SI or 12SI. Over the years the Leece-Neville 8MR alternators were installed on many Perkins, Universal, Westerbeke, Cummins & Volvo diesel engines.

    Built in Maine: These alternators are hand built, & hot run tested, in the shop right here at Compass Marine Inc.. This ensures a quality product at a very, very fair price. This alternators is not just a few dollars less, it costs hundreds less than the competition.

    Some of the components are made overseas, some in the USA, but we sourced & physically tested for the best components we could possibly find to meet the value to performance ratio we were looking for. For example the rectifier in this alternator costs 5X what the rectifier used in an automotive grade alternator would cost. The rectifier uses six 70A diodes for a cooler running alternator and an automotive grade alternator would use 25A diodes.

    Our CMI brand alternators are specifically designed to fill the gap between an ultra high performance alternator (see the other alternator offerings such as Balmar & Mark Grasser DC Solutions) and the factory alternator. It was designed to meet a price and performance niche not available to boaters previously. This is a what we consider a n excellent medium duty alternator not a light duty automotive alternator.

    The CMI-90-ERM comes standard with a tachometer output (stator tap) for diesels that run the tachometer sense off the alternator. Not all diesel engines drive the tachometer from the alternator, but some do.

    The CMI-90-ERM is set up for external regulation only. It has no internal regulator though it may look like one. We are custom manufacturing our own field connection pathway for this alternator and it uses what looks like a stock internal regulator but it is not. The conversion from internal to external regulation still uses the factory located plug positions instead of a cheesy pig tail of wires dangling out of the alternator frame for the field & stator. The terminal marked "F" (left side if looking at the alternator from the back) is the field connection and the right wire, marked "S" is the stator tap or tachometer feed.

    Special features:

    • Intended to fit & replace a Delco, Bosch or Leece-Neville / Motorola 8MR series.
    • 110A cold rated & 90A hot rated with good high idle performance.
    • High amperage rectifier with six 70A diodes and more cooling surface area.
    • Machine wound stator of 14GA top quality magnet wire means better cooling and higher temperature tolerance.
    • Precision machined rotor and slip rings for greater contact at all RPM.
    • Tighter tolerance of stator/rotor gap for better performance.
    • High copper content brushes. This yields excellent conductivity and longer brush life.
    • Ready to accept an external regulator (we recommend only Balmar regulators).
    • 1/2" / 13mm single v-pulley or 3/8" / 10mm single v-pulley (please specify when ordering)
    • Billet machined pulley not cheap stamped steel.
    • Hand built in Maine by Compass Marine Inc.
    • 1 or 2" foot mount - includes spacer and shim for varying bolt diameters.
    • Heavy Duty 5/16" B+ terminal and 5/16" B- terminals