I’m not sure that this is quite new thread worthy, but here we go.

I put a brand new Arco 65050 75a alternator on when reinstalling the engine, and I’m only getting 11.5 bolts out of it. It seemed like it worked for a bit but was honestly more focused on the other vitals to notice, but I do remember having some good voltage for a little while.

I messaged Arco and they just said “Tighten the belt, dummy!” And so I got a 3’ pry bar and pulled on it until the thick mounts were bending and cinched her up. No difference.

Ill try putting the old 120a back on and test it and send this one back to Arco to bench test but if anyone has any thoughts I’d appreciate it.

It is charging three batteries but 75a should be plenty? I’m reading voltage off both the old dash gauge and the Holley handheld computer. When I put a meter directly on the lugs the first time voltage actually dropped when I gunned it.

I would give them a phone call and speak with a tech. They helped me through an issue I had with over charging. There is a wire coming back to the internal regulator from the starter that I accidentally taped up in my loom and hadn’t connected. Doh! They are very helpful over the phone. Good luck

3 fairly new or brand new batteries, and they do take a charge. I charge them up to 12.7 at home then they drop to 11.5. At 11.5 I can watch on the Holley monitor it bounces around between 11.4-11.6 but never really drops below that even after an hour of running.

No local shops around to bench test it. I took it to oreillys and that was hilarious watching them try. To their credit the guy actually tried to sort it out. Never even made it to the test machine.

Ill do a few more troubleshooting ideas then then give them a call.

I actually went into a CarQuest lately for wheel lugs for the trailer, and the dude actually busted out a real book and helped. #mindblown!

Would the canon plug have any effect on charging? Seems like it shouldn’t and just communicates with the dash, but tracing everything possible. I put an ohm meter on the ground lug and had great connection to all of the negative posts. Solid reading from the + lug to the starter as well. *shrug*