First thing I'd check is the tightness of both starter bolts. If either is loose at all, I'd make a note of it. Then I'd pull it and look at the little gear on the end to make sure it was nice. Then put it on the bench and get a battery and some jumper cables and check the mechanism that makes it shoot out and engage the flywheel.
Then I'd get a flashlight and a breaker bar and slowly turn the engine while checking every tooth on the flywheel. If any were buggered up I'd think about changing that out asap.
Finally check the other three bolts/nuts/studs holding the transaxle to the engine. I don't know the torque spec for these offhand but I'd be sure to make them tight.
If everything looked good I'd put the starter back on and figure it was a weird glitch.
But my guess is, if you look carefully, you'll see something that's obviously not as manufactured.