Motor wont start, could be a battery issue.

We got my brother in laws boat back in the water on Saturday it is a 2005 28 Grady with twin 250 4 stroke Yamaha's. The starboard motor started right up but the port motor would not start it just made a clicking sound but the starter would not engage. The boat had been sitting for a while so we figured that the port motor battery was dead, put the battery switch to both and it still did the same thing. We ran the boat around to the slip on one motor and pluged it in to shore current to charge the batteries up, after an overnight charge same result. Going to get all new batteries but I wonder if something else is going on as I would think that by switching to both on the battery switch it should start that motor. Any thoughts on what could be going on or is this normal?

Re: Motor wont start, could be a battery issue.

A bad battery cannot be jumped nor charged which is essentially what you do when putting a battery switch in BOTH. Put a voltmeter on the battery while someone attempts to start the motor. Bet the voltage drops like a rock indicating a bad battery. That all assumes of course that the engine is not locked up. Remove the cover and try to turn the engine by hand.

Re: Motor wont start, could be a battery issue.

If you switched to both, it should have started off the second battery if the first was low. Check your cable connections and don't forget the black ground is just as important as the red positive.

Re: Motor wont start, could be a battery issue.

Get a multi-meter and check the voltage of each battery (Battery switch off).

Putting the switch to both isn't going to help if both batteries are low. Is the motor EFI or a 4 stroke?

Re: Motor wont start, could be a battery issue.

They are 4 strokes, the motor is not locked up. He had a mechanic look at it today and it appears to be a ground issue with one of the wires on the onboard charger, the one battery is low the other is fine.