I have a real dumb question or two....Where do I change the oil on a 420 Megablower? And is there a way to check the oil level? its starting to leak a little on the back side of the case but I would like to be able to get through the rest of the season before I get a new blower or have this one rebuilt. Is there a certain procedure to follow when changing the oil on these things?

Thanks!

Ther rear uses greased ball bearings, not oil. If you are seeing oily residue back there, the rotor seals are shot and fuel is dissolving the grease and boost pressure is pushing the sludge out.

Better gettem looked at asap because the rear bearings will grenade from a lack of lubrication.

The front are oil bath lubed. Remove the pipe plug beside the drive snout, suck out the oil and refill to that level thru the pipe plug at the top of the casting.