Volatge Regulator Melt Down

I guess my idea of rewiring the new to me boat was not such a bad idea after all.
Should have listened to myself. Looks like over loaded wiring at my battery and perhaps a lose wire somewhere caused my voltage regulator to melt down and catch fire.
MY 2003 75 hp Mercury went into rpm limit or perhaps it was just the reg shorting , when I looked back I saw plenty of water peeing out, shut it down then smoke started pouring out of the cowl. I wanted to see what was going on but was afraid if I opened it up a fire would break out. Instead I just waited until it stopped smoking with extinguisher in hand. Got a tow into the ramp and hauled it home.
Looks like I will need a new regulator and wiring harness along with whatever else is scorched in there.
Good news is despite what it looked like at first the engine did not get hot.

Any recommendations for the best prices on Mercury parts sales?

Attachment 263792

Here is a good place to look up diagrams and part numbers. Also can look on iboats. Then write down part numbers and Google search for best prices.
Marine & Boat Engine Parts - Boat & Outboard Motor Parts

I use the website Cray posted to look up the part number, then I google that number. Very often I find prices much lower in other places. My last two parts I found on Amazon, which was almost half of what other places wanted.

Thanks folks!

Might want to inquire at a Mercury dealer, there was a service bulletin for some rectifier regulators on Mercs a few years back, I changed quite a few. See if your motor was involved in an update , if so was it done , and if done to make sure you get the correct part number, not all websites will have the updated parts umber lsted