Changing out some engine components on a "new to me" 1985 Oday 28 with M12 engine. Purchased new alternator specifically advertised for the M12. Appears to be a 3-wire with internal regulator. Found a Universal engine wiring diagram which shows the battery connection and an ignition wire for excitation (which had not been connected to the old alternator - I wonder why?). But I am not finding or seeing on the wiring diagram a sensor wire being used. Is this a common installation? Or should the sensor wire be connected to the battery terminal of the alternator (which is common on many cars), or should I find another sensing source? If so, any suggestions location for a two battery setup with inverter/charger?
Alternator wiring
- Thread starter envisionvenicefl
- Start date
Need more information on this one. Lot of scammers out there selling incorrect alternators. What brand & model alternator did you get?
Thanks Maine Sail, here is the link to the alternator I bought. ALTERNATOR UNIVERSAL MARINE 5411 5416 5421 5424 5432 5444 M12 M15 M18 M20 M30 | eBay
Sorry to say but you did not get the same alternator you originally had on your engine. The stock alternators are a high quality Prestolite/Leece-Neville and your eBay seller is using LN stock images to scam people into thinking they got a Leece-Neville alternator. This sort of BS runs rampant on Amazon and eBay and from disreputable vendors. We have access to that exact alternator and they are making a nice margin selling you what is essentially a counterfeit marketed unit.
What you got is a low grade Chinese clone marketed as a Leece-Neville compete with Leece-Neville's stock images.. I know this because we buy direct from Prestolite/Leece-Neville (we are a manufacturer of alternators) and our wholesale cost, on a genuine Leece-Neville, is a LOT more than you paid at retail.
What you got is a low grade Chinese clone marketed as a Leece-Neville compete with Leece-Neville's stock images.. I know this because we buy direct from Prestolite/Leece-Neville (we are a manufacturer of alternators) and our wholesale cost, on a genuine Leece-Neville, is a LOT more than you paid at retail.
If you still have the original Motorola alternator, then consider having it rebuilt at an auto electric shop and return the eBay purchase. I also have a M-12 engine and had my alternator rebuilt for about $75. If you have the typical M-12 trailer wiring harness, then this is a good time to get the high amperage charging circuit and starter circuit out of the wiring harness which is prone to overheating as detailed in MainSail's article. I ran a new 4 gauge wire from the rebuilt alternator directly to my battery compartment and added a Blue Sea ACR to charge my two batteries. This allowed my to bypass my battery switch which can fry the alternator diodes if you forget and operate the switch with the engine running. I replaced the amp meter with a Faria volt meter in the engine panel.
