smoke/exhaust is this a bad sign?

So I was pretty excited to get out on my boat that I just purchased yesterday. It looks great and runs good, but there is smoke coming up out of the water right under the swim step. I don't know boats at all, so maybe this is normal. It's an older boat 1985 Supra. Smoke is barrelling out from under the boat and also seems to be coming out the 4 exhaust holes on the boat. A lot of smoke when you step on it to pull someone out, and still when you're just ridin. Any suggestions please?? Is this normal for an older boat or did I buy a lemon?