boat will not start

I bought a 1973 thompson with a 350 corvette engine, i bought it in the middle of winter, did not try it bought as is, when i tried it the other day it grunted a couple of times small grunts, i put new batteries and it will now do nothing, not even a grunt or a click. i jump the solenoid with a scdrewdriver and it make s a whirling sound and that is all i get, is it i hooked batteies wrong? when i had the plugs out , i sprayed blaster in the cylinders to make sure it was not locked up , can you give me a clue where to start without spending a small fortuen, thanks greg