Starting Issues

Hey Guys, so when I try to start the boat on the first turn of the key, it won't start. The engine won't turn, just seems dead. If I turn the key maybe 2-3 more time and just hold it in the start position, it will fire up usually right then. Once started, I have no issues starting it again from that point on, unless it seems to sit for say several days or weeks. I've just changed the key ignition switch thinking maybe contacts were going bad, but still the same issue. I doubt it's a fuel issue cause the motor doesn't even turn. Maybe it's a starter issue? Any ideas on what it could be, or where I should check next?