Hot alternator and no start

[Dodgie_]

And I mean temperature!.

My Yanmar 1GM was working fine until I replaced both 12V batteries as part of a cleanup.

I briefly wired them up as a 24v setup instead of 12v. Dumb.

They are now wired with each positive to a terminal on the battery switch and the red wire going to the motor to the common/feeder. The two negative terminals are wired together, with one also connecting to the black wire going to the motor.

On the panel, with the starting switch in OFF, I noticed two lights glowing dimly - Battery Charge and Low Oil Pressure. When I turn the start switch the LOP goes off, the Battery Charge light brightens and...nothing.

I tried it with one battery only bypassing the battery switch (ie direct red to positive, black to negative) - same result. While poking around in the engine I put my hand on the alternator - and it was HOT.

Batteries are fine and running everything else without problem.

So - I am assuming:
- electrical short?
- in the alternator?
- or the starter?
- because of the 24v?
- or stupid has wired something else incorrectly?[LIST]

Advice, suggestions?

Dodgie

[MacGyverRI]

24v would have fried the Alt. and/or Regulator along w/ the starter solenoid if you tried to start it.

You may have also fried starter wire going to the solenoid.