Well from the sounds of it I will bet it is the front bearing if everything else is sealed up. You should be able to get a new front bearing here.
http://www.avidrc.com/?action=item&id=60 It might be worth the 5 bucks to find out. Contrary to popular belief the front bearing is not air tight. The seal is there to keep the dirt out of your engine. Most will leak a little fuel but not much. If you have fuel all over the chassis then the seal is or has gone bad. Do run a washer behind the collet for the flywheel? If you do this could be your problem. If the washer is overlapping the seal and is rubbing it will get the seal hot and ruin it. I found this out the hard way. I still do it some times but I put the washer on in a way that it is not touching the seal.
Bump