2008 Mercruiser 3.0 Voltage output?

S.Lee

Seaman Apprentice
Joined
Apr 20, 2005
Messages
40
Hello,
Was late getting my boat out of storage and only got it ran up yesterday. I noticed that it seems to be putting out a little too much on the alternator. Granted, I never took it out on the water to see if it would drop off, however, I am looking to see what other's experience have been.

I have owned this boat for the last 7 years, and have not changed what I have done. Yesterday, I pulled the boat out of the shop and installed the battery. Cleaned all the cables, and started it up. It ran well, however I noticed at first it ready about 15v on the gauge on the dash. I put a voltage meter on the battery and in was reading around 12.6. I thought no big deal, and cleaned the cables again and tightened them down. Then restarted and the meter when to about 14.5V. Both on the gauge and on the battery. I let it run on the muffs until it warmed up to the point that the thermostat opened. never say it start to go down. The battery measured 13.1V with the engine off.

What have others seen? I am thinking the next step is to take it out on the lake for a bit and run it and see if it drops down. It may be that the battery could be a little bit low, I did not check to see the water level in it. but to me this is a shade high......
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
You have a perfectly normal system. A battery fresh off charge will register high but drops off the surface charge quickly. 14.5 volts running is perfectly normal.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,282
Cleaning your connections also helped
 
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