Solenoid problems

OK so I have a '77 evinrude 25 HP and I just replaced the starter solenoid because the motor would not start unless you tapped on the solenoid while turning the key. I replaced the solenoid with the new one I ordered from iboats. Now when I turn the key, the solenoid will just make a humming nose, and the starter motor will turn SLOWLY on occasion. But when it turns it turns real slow, not enough to rise up into the flywheel let alone turn the motor over. Any ideas as to what might be happening here? Thanks, Mark.

Sure your batteries good?

Jump start with battery & by pass the solenoid & go directly to the starter.

I just charged the battery a couple of days ago but i guess it is possible it is bad. Worked fine last season though. Could I hook my car battery up to it or would that do damage because it's not a marine battery?

Make sure all of your electrical connections from the battery all the way in are tight and clean.