Please help!!!! Evinrude 40 electrical problems

[MercPower]

I have an Evinrude 40hp VRO that will only start when hooked to jumper cables. Had the battery checked and they said it was weak.
Of course I plan on replacing but was wondering if there could be a bad alternator??
I don't know much about 2stroke but someone told me you have to charge your battery before every trip.

Is this accurate? Is there no way to charge the battery on the water?

Help would be appreciated!

 

[Barnacle_Bill]

Re: Please help!!!! Evinrude 40 electrical problems

Someone told you wrong. A deep cycle battery used for trolling motors should be recharge immediatly after every use. Your motor should keep the starting battery charged. Check the voltage at the battery with the motor off thne check it again with it running. As RPMs increase you should see an increase in voltage up to 13-14 volts.