Chrysler 360 Killing Alternators


New member
Hi all,

First time poster here, I’ve done some digging and can’t seem to find a similar situation.

I’ve got a 28’ Marinette Express with a single 360. Last summer my mechanic broke my alternator while trying to adjust the belt tension. It was an oem multi wire and I replaced it with an Arco single wire. It took me a bit to get things shimmed right, but it was working.

Fast forward to three weeks ago and I notice on the voltmeter that my voltage is slowly but surely dropping below 12v. My starting battery ends up dead and I got another alternator as well as a new battery.

I replaced the alternator and the battery and fired everything up. I had 13+ volts at the battery with my multi meter, so I let it run while doing some other work to charge the battery. Shortly after that I started to smell an electrical/rubbery burning… at first I thought the belt was breaking in, but it was cool to the touch and the very light smoke seemed to be coming from the bottom of the alternator.

Now I have 12.3-12.5v when the motor is running (both at the battery and directly off the bat post on the alternator. I’m assuming that this new alternator is toast, but I’m trying to figure out why.

My grounds/negative connections that I can easily see/access are clean and tight. I don’t have any other apparent gremlins besides maxing out rpms underway at 3500 (need to look at my rotor and clean the hull) but I don’t think the two are related.

Anyone else experience this? Any thoughts as to what I should look at next? I’m going to call Arco in the morning, but I have to imagine something that is amiss is causing the failure.

Thanks in advance.

assuming you don't have a wiring issue, two "maybe's" come to mind....bad / missing ground wire on the alternator and bad battery.

Ideally, you can check the charging current and the voltage with the engine running after start-up...

After running '1-wire' setups for a few years, I'm convinced the more conventional three wire system is a better setup on a boat...most people like them for their simplicity...with the newer battery technology available today, the sensing function is key to a long service life...
This begs the question of why it was your responsibility to replace the alternator that ding dong busted.