reversed batt. connection

[LarryQ]

I was changing out the batteries on a late '90ies 40hp when I accidently reversed a battey connection. Heard a pop from the front of engine and had smoke come from the cowling. Pulled cowl but no damage seen. Engine will turn over but I didn't try to start. How much damage did I do? What needs to be replaced?

[boats.net]

Could have damaged voltage regulator and possible wire harness.