Is my Alternator going out?

[switchme]

Last night I noticed that when running around 3,000 RPM the volt meter read around 11.5. Seems to me that it should be around 12.5 - 13 to keep the battery charged. Nothing was on except the depth finder, PP & taps. At idle the volts dropped to around 10.

If it is going out should I replace it with a larger Alt? I don't have a large stereo but may add one later.

The engine is MP 335 MPI.

[Coach]

You might want to do a full charge on the battery or test the battery first, then see if you are still getting the low reading. You don't need a bigger Alt. If it is the Alt then just replace it with what is in there now.

[dogbert]

Last night I noticed that when running around 3,000 RPM the volt meter read around 11.5. Seems to me that it should be around 12.5 - 13 to keep the battery charged. Nothing was on except the depth finder, PP & taps. At idle the volts dropped to around 10.

If it is going out should I replace it with a larger Alt? I don't have a large stereo but may add one later.

The engine is MP 335 MPI.

I would say yes. It's either the voltage regulator on the alternator or the entire thing. I had to replace mine because it got wet one too many times (lots of surfing = water in my bilge).

[rogersbm82]

Mine was doing that last year, replaced the alternator and all was well.

[gman]

Check your connections to the meter. I had a very loose connection and mine was doing the same thing.

[jchurch6713]

I had the same problem a couple of weeks ago. The only difference is that before I ever noticed the gage reading low my battery was draining when the boat was in storage (it's always connected but I am now in the process of installing a Perko switch and an extra battery). I took the boat out and noticed the low voltage and when I tried to adjust the taps the voltage would drop to zero. I replaced the alternator and aleviated all of my problems.

[lee]

I have seen the wire connector on the back of the alternator break and not make a good connection.