[Dave at Pelican Parts]

Sounds like a pretty good chance you spun the motor backwards, then. Check all your hoses, and everything in the intake system for anything that could be damaged by overpressure. Check the MPS diaphragm--use a vacuum pump, not your mouth, because you can't create enough of a vacuum for long enough to get meaningful results. You can only tell if it's really bad without the vacuum pump. (You can get a MityVac for fairly cheap.)

--DD