battery Life

[stevew]

Hi there ,I have a small runabout with a 70hp. I have had the boat for a year. Just lately I have found it just turning over then kicking into life at the ramp. After it has been started once it turns over fine. The battery says it's charged on the indicator, but it is 8 years old. Is there a point where a battery will loose its inital cranking power ?

I have tried charging the battery over night , but with the same result.

I have just tried jump starting it off the car, the results are the same. The battery had 12.1 volts before I tried starting it and was charging at 13.8 volts when the motor was running at 1000 revs. When I shut the motor off the battery slowly discharged at the rate of .1 volt per min.

Do you think this is a battery problem or a contact problem. I have cleaned and scrapped every contact point so I'm sure there is clean contact on the battery and the motor.

Many Thanks
Steve

[PKaminsky]

At the age of 8 years, I would suspect the battery for sure. I change my boat batteries every 4 years for reliability. The cost of a tow or jump start can cost far more than the cost of a battery. The battery static charge should read around 12.6 volts and hold with no load on it.