1993 BF Nautique Electrical Gremlins

rileylaker wrote: Where it gets weird is with the new alternator. It's like it is not putting out more than 11v at idle. Tested the batter w/o engine running and got around 12.4 v then again with the engine running and got 13.4 ish volts so seems like it's getting ok voltage. So why the PP power cycles? PP volt gauge is reading 11v which makes sense why it's cycling.

This probably has more to do with just dash wiring issues than anything. Usually with the engine running, you get enough of a voltage boost to overcome the weak wiring. But, at the end of the day, the positive feed to the dash is probably marginal, the dash power breaker could be weak, the wiring from the breaker to the key could be weak, and the key itself could be weak. The stock wiring is pretty skinny, and you could be losing volts, which Perfect Pass doesn't like.

rileylaker wrote: Does anyone know for certain if I need to attach that "exciter" line that was originally connected to the stock alternator back onto a 12v source like alt output? Or can I leave it tied back?

That's a tough question unless you know what the alternator needs. If the alternator doesn't call for it then you don't need it. Try to see if you can get a wiring diagram for that alternator.

Thanks for the responses guys. Was away from my computer all day.
I will do some more investigation with a tester this weekend.
Some more details to ponder in the mean time:

Bought the boat 3 years ago after it had been sitting for 5 years. As soon as I bought it, I put in the PP and it always seemed to have low voltage issues causing it to cycle at idle. Turns out the alternator was pooched so I replaced it. With the new alternator, the volt meter on the dash went from 11v with the old one to 13+ with the new one so I thought I had that problem licked. In an effort to help the hydraulic sun pad function better I ran some 8 gauge to the hatch power and then grounded the entire dash a 2nd time. Made the hatch work way better but I did not run a 2nd positive to the dash itself, just to power the hatch.

Where it gets weird is with the new alternator. It's like it is not putting out more than 11v at idle. Tested the batter w/o engine running and got around 12.4 v then again with the engine running and got 13.4 ish volts so seems like it's getting ok voltage. So why the PP power cycles? PP volt gauge is reading 11v which makes sense why it's cycling.

The old alternator did not have a volt reg built in as it was original '93 PCM issue. The new one was from NAPA and is their own marine brand with the integrated volt reg. New battery, no change.

Some great suggestions above so I will clean all terminals and add dielectric grease as well and see what results I get. I will also retest the output of the alternator at the back and at the front and post the findings.

Does anyone know for certain if I need to attach that "exciter" line that was originally connected to the stock alternator back onto a 12v source like alt output? Or can I leave it tied back?

Could the original voltage regulator be causing me any issues?

Thanks in advance.

Cheers!

The one wire alternator just has one wire it the output, the case grounds to the block so any ground wire is getting a ground from the alternator.   They aren't the best idea because they don't have any way to sense what kind of output the need. They're fine for a regular load, but when you start adding lots of options like heaters, stereo ect they don't know what to do and that can cause issues.

I had to spend the writer actually learning how an alternator works and why the boat is wired the way it is. I learned a few interesting things along the way. In addition to the need to have more than one wire I also learned why there is a difference in in which way the alternator rotates. I've always thought it didn't mater and while that is true for the output, the direction the fan turns does make a difference.

Jake,
One more thing. You didn't by chance get the new alternator at Autozone did you?? If so, then you sure went to the worst place!! BTW, hopefully the new one is marine rated.
Also understand that with a higher amp alternator, you do need to upgrade the wire size. Just a new ground wire isn't going to do it. Have you increased the load from the dash.

8122pbrainard wrote: Jake, Clean ALL connections and use dielectric grease when putting them back together.

+1
Dielectric grease should be in every boating tool box. Keep in mind with 12v DC, there is no such thing as "too big of a wire" so hopefully when you run new wires you keep this in mind. With 12v DC, resistance is a battle, if the connection looks questionable, then no doubt it is bad. Don't forget connections in the engine bay too!


I don't know if this will solve the gremlins but it definitely is additive.

It's the undersized wiring to the dash that's most likely the problem. Brian, Bri892001, has some good treads with pics about how to fix it.