When I am idling, my voltage is dropping down to the 10 range and then I lose all power. When I rev the RPM's, I can see the voltage go up to 13-14 like normal. I checked the alternator and it's all good and the batteries are fine, killed the stereo and same problem. Anybody seen this or have any ideas?

enough tension on the belt??

my alternator belt it as as tight as i can get it.. the other belt is a bit loose but not sure how to tighten that one yet.. any reason why the other belt should be loose? The alternator belt is tight though...

Check the channels that the belts run in. Sometimes when the belts get loose, they leave dust or film inside that allows the belts to slip. May be time to chenge them out. If you do clean the pulleys with rubbing alcohol to clean them up. Belts should be tight enough to not slip but not so tight as to cause the alternator to "deflect" toward the crank. <BR> <BR> <BR>Eric

Thanks for the help guys. I will check, tighten, and clean both belts tonight. If that's not it, any other options? My volts are dropping so low at idle that my engine is shutting off. The big red Low voltage light flashes for a minute then engine off.

I just talked to my shop and even though the boat is all of 1 yr old, they can't get me in right away. They said it sounds like there is a big draw on the battery coming from someplace but I can't find anything pulling from it.

Tony, <BR> <BR>What kind of amps are you running? Some of the class D or T amps use pulse width modulated input sections that pull significant current when playing at low levels. It's kind of a reach but an outside possibility. See if the voltage is still low if the stereo is off. Also see my post on PN. <BR>

I have heard of people running a smaller pulley on there to make the alt work at lower rpm's

Do not trust the volt meter on the dash. Instead use a good volt ohm meter. <BR> <BR>Does the boat crank specifically, restart secondly, after stalling?

Sounds like it's time for a new alternator. The brushes wear and nolonger function well at low RPM.