i had the same prob. when i took the plate off, the thing was not even screwed in it was just flopping around inside. i screwed it in as much as i could and now it still does it but when the motor warms up it goes away. i dunno what else to do to fix it but i guess im just gonna leave it like it is since my new motor will hopefully be going in soon.

watch out tho if you take the plate off, the bolts that were holding the plate on mine were crappy and both of them broke off before i got them out so i had to do some fixing.