Last year I replaced my boat’s alternator. It was partially submerged when my boat was flooded last year, and it didn’t work anymore. Might as well, the 35 amp original Motorola unit was slow to charge. Most people opt for the proven option from a popular Atomic 4 web-store and engine builder. The problem is, it isn’t a cheap unit — $230 dollars. It is indeed a Motorola unit, which probably has a higher quality and is a proven brand. However, based on my experiences with cars, off-brand alternators work just fine and last for a long time, long enough where I never see it fail before I sell or junk that car.

I’m lucky to live so close to Annapolis, Maryland. Over there, auto parts stores carry replacement parts for common marine engines and convenience stores will have PFDs in stock. Battery stores will have marine batteries and you guessed it — alternators. I originally sought to rebuild the alternator to save money, but the quotes were too high. So with some advice from my marine mechanic friend, I called some battery stores in Annapolis.



Paydirt! A tech from Pasco’s Battery Warehouse in Annapolis knew exactly what I needed. They quoted me the price, then I called the manufacturer to make sure its approved for use in a marine engine bay. It was! The particular alternator is a replacement for a mondo/mercruiser power boat. It drops right in and bolts right up with the existing hardware. Any compatible belt will work. The tech at Pasco’s even moved the signal wire to one of the posts (I think ground, I can’t recall, but see photo above.) Best of all, it is a 65 amp generator. The way regulators work in alternators ensures that your battery will not overcharge, even if it was a 100 amp generator.

Part number: Arco Marine 60065

Price: varies, typically $160-170

Tech at Pasco’s informed me that there is a 75 and 85 amp alternative as well.

Hope other Atomic 4 users will see this and save some money!