rotisserie motors are your best bet. I have built a ton of FCG's in the past with that type of motor. They are powerful and most important WATERPROOF...
How far out you put your horizontal rod plays a big part in it.P.S. To the guy who suggested the disco ball motor... I tried that already and there is no where near enough torque. Its great for turning things on an axis, but not turning a crank. If you got it to work somehow, props to you... maybe you found a freak motor or something. lol.
I am torn between the gearhead motor:That should work fine if you're talking about the motor that runs at 12 volts DC.
Ane yes, just wire it directly to the motor wires. And add a switch too if desired. If you want the DC motor to spin in the opposite direction just reverse the wires.
Even this adapter will work fine:
Heavy Duty 12VDC 500ma Adapter-The Electronic Goldmine
The more milliamps you can get from the power adapter, the better.