Put the key in the run position, take a pair of rubber handle insulated pliers or something equivalent so you dont get shocked, and bridge the two posts on the starter solenoid that is next to the starter. If the starter spins, then you solenoid is toast or you could have a bad connection as stated in the previous post... If you are not in the water, or hooked up to muffs, pull the spark plug wires and only do it for a VERY brief second to see if it spins...
