Thanks, Brian, that's a good start.

My friends large OS 4-stroke uses about an ounce of fuel per minute. In 2000 hours that would be 2000*60 ounces. One gallon is 128 oz so that would be 2000*60/128 gal.

If you were to do it today at $20.00 (US) /gal that would be $2000*60/128*20.
$18,750. Anybody want to try it? :-)