Won't turn over?

So I took my 85 SN 2001 out on the water after doing all the maintenance and in ran great. I came home and parked it for a week and went to fire it up and it's like there is almost no power to the starter. When I turn the key to the on position all the gauges work. When I go to start it it won't even turn over like there is no power at all. I'm pretty sure the battery is good. Any suggestions? Thank you.

Greg,
First, I suggest checking the battery cable connections. Use one of these:



Are the cables in good condition? Condition of the battery? Is the battery a starting or deep cycle? Is the start relay (solenoid) energizing? Get voltages with the ignition switch in the start position at the battery lugs, then the cable terminals on the battery, then at the cable to the start relay, then at the cable out of the relay and finally at the cable on the starter itself.