One of my friends and I use to detail boats and winterized them to.
you can go to any proper marine store, it doesnt really matter if its fresh water or salt water store.
but what we work with for wax was (Collinite boat wax) this stuff works awesome. and you can use it on your car too, i think it cost about 18 bucks. and actually anything from (3M) products works great.
and (Collinite boat wax) has (Collinite metal wax) this metal wax is awesome i really recommend it, but your gonna put some muscle into it, but the out come is awesome.
And if you get any scum lines on you outboard, trailer, anywhere. i recommend ON/OFF you can pick it up at a marine store. becarefull this stuff is a acid and it burns (trust me i had to learn the hardway)
try not to put dishwasher soap or simple green on your boat. this stuff can strip the wax right off and also your clearcoat.