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*

Yes.

Theres two wires in the harness and I connected the red to red on the alternator and then the remaining two. The + and - lugs are pretty clearly marked.

The harness has a red with purple stripe and purple. I hooked up the red with stripe to red and purple to the other. Any chance those are backwards?

https://cimg5.ibsrv.net/gimg/www.off...6ca4c64b1.jpeg

Yep. The big red and black are pretty obvious. Full disclosure - I’m colorblind as ****. Most often I’ll send a pic to my girlfriend so she can tell me what I’m looking at. I just connect the two brightest wires together then the two darker wires together. Luckily I can tell the big red and black apart. :p

The Arco seems to be a solid little unit so I expect the issue lies somewhere within my retardedness.

Hopefully the GF steered me in the right direction with the colors;)
https://cimg5.ibsrv.net/gimg/www.off...afad83773.jpeg

Arco said to replace the belt as it’s probably glazed. Sound legit? Anyone know the cross reference for the 57-48122 belt? 48” 29/32” top. I’d like to grab one from the auto store today as I have time to dick with it. I’ve had no like cross referencing.

DONT MAKE ME FIX MY OWN DAMN BOAT! :p

Thanks for the info, SB. :thumbup:

The 120a is a car unit that came on the boat. I switched that out to a 75a DB marine unit that corroded into a puddle of rust. The Arco vendor suggested this one. Even with the batteries disconnected I’m only getting 11.5 out of it.

Thanks for the pointers, AllDodge. A quick check showed that I had it hooked up correctly.

I may have found the issue(s). The boat is in a remote storage and a pain to work on especially with a hose. When I checked the output I believe that Arco May have been correct that the brand new belts were slipping but I had already yanked it off. When I put it back on it behaves a little differently but still not charging well.

So as I was yanking it off again the positive ring connector came with it. It looks as though there may have only been 2 or 3 strands still intact. Enough to pass a continuity test but effectively charging three batteries with a 22gauge wire. I had not rechecked the output since the first time as it’s such a pain where it is located.

All of the batteries are topped off via a charger and everything buttoned up and hopeful that was the issue. I’m not sure when I’ll get to put it to practice though yet.

Yup, those were the issues. Ham fisted shade tree hack with 20 year old wires. Steady 13.6 at a blip over idle. Thanks for the help as it all helped.