Dash guage reads 15V at idle. A bit higher while cruising. Double checked dash gauge against a separate voltmeter across the large orange (BATT) lead and ground. Same 15 V reading.
Had Alt checked at Alt and Starter shop, checked fine.

Tech says I have a problem in the wiring going to the Alt. Specifically the red 12v line lead at regulator. Says I can double check while on motor and running by disconnecting the red 12v line lead at Reg and touch the Reg lead side to the large orange wire. Volt meter should drop to 12-13 volts.

IF it does drop as he suspects, what does this mean? Red lead going to reg. have a short or open? Should that wire always have a constant voltage? 1 yr old battery issues?

Any sugggestions would be rewarded with a big thanks!

BTW, Mando alt.
'99 502 EFI's

Jerry

Regulator lead should sense actual battery voltage. Your goal is to restore 13.2-13.4 volts to the battery while powering all the other DC loads.

Start by checking ALL of your DC connections from the battery to the DC buses and motor harnesses. Also be sure to check the ground side of the equation as well.

For whatever reason, if your gauge is reading reasonably close to actual, your regulator is getting a degraded voltage signal. Maybe you got minimal wire sizing on the bus that feeds both a significant DC load AND the regulator. The load would be sucking more current than the wire gauge freely allows and you might be sending a lower voltage than the actual battery voltage.

For temporary kicks, run a new wire directly from the battery to the sensing lead for the regulator. See what tht does.

Ok, so unplug the red wire at regulator, then run a test wire from the battery to the red wire lead going into the regulator?

Also, forgot to mention;
I checked the battery voltage at battery= 12v. The dash will read 12v with the key on(which sounds right) then as soon as the motor starts, climbs steady to 15v within a few seconds. An increase in throttle, rises the voltage a hair more.

Boat is 2 1/2 hrs away at lake. Will trouble shoot this weekend and post results.
Thanks!

Wiring goes in this order:
Large orange alt output to the starter. There it splits to the battery and to a smaller red wire. This red wire provides voltage to the entire harness through the breaker. It splits to the key (your 12 V guage) and to the sensor wire to the alternator. If you have resistance between the split and the alt, it will read lower voltage and try to compensate (also compensates for drain and wire resistance). Check the connections of the red (or red/purple) wire from the breaker to the alternator for corrosion or kinks.
You can also cross the output of the alternator (orange) directly to the red wire sensor post, as was suggested. I've wired 4 wire alternators on 1 wire harnesses this way and it worked fine.
Gary

I just had the same issue with my system. Everything you guys said is correct. I don't know what your alt. type is but, I have a small pot. on the inside of my brush cover mounted in some kind of epoxy. I belive is will adjust the regulator circuit. I must say I did not change the setting on mine after talking to the alt./generator shop(where I exchange units). Also the local marine mech. told me it was ok (15.5 volts). So as long as my wires check good(Orange-batt. line/starter, black- gnd, red-12v constant, purple -12v switched) I've been out several times and all seems ok. I haven't smelled an over charged batt. yet.

I thought an alternator was suppose to put out between 13.8v-15v shooting for 14.4 volts?

This definitely needs to be addressed or you will cook your batteries in a hurry.