Very odd battery problem

[lakebait]

Hi there. I am new to boating...just bought a used blackjack 26.

i am using 2 nimh 4300's. ir ran well for about 2 minutes, then showed sign of low battery. I swapped the leads on the batteries and it went back to full power for another two minutes, then died.

it seems that it is only drawing from the left side battery, even if i change batteries.

has anyone ever seen this before?

[crash440]

Is it stock setup? If it is then it is wired in a series right from the factory, So that being said the boat can not complete the conection without both batt. being conected. So it is one or two things, Are they older packs? If so they could be weak batt. Thats why it only lasted 2min. or there is some kind of drag on the driveline,being the flexshaft or motor . you have to undo the flexshaft at the motor and pull it out and grease it,I do my every 3 runs. If that was turning free then I would suspect the motor then. hope this helps.