Filament feed through barrel and nozzle (1 reply)

Hi All,
I'm another new reprapper, joining the fray with lots of questions and very little experience. So please excuse my improper use of terminology (and feel free to correct).

I've just gotten around to putting together a Prusa Mendel kit I purchased from Mixshop a few years back.
This is the one for 3.0mm Filament (PTFE and Barrel) with a 0.5mm nozzle.

On the many problems I'm having is that the extrusion does not appear to be working very well and even often pushes the PTFE rod out of the extruder. I've tried changing the tempreture from 185C on up to 210C, but I don't think that's the issue.

For one, the filament does not feedeasily through the brass barrel (which after reading some posts here, sounds like it should?)
As the PLA filement is 3.0mm itself, possible mix up with the size? Is there a way to widen the barrel, should it be done, or would it be better to look for an alternative barrel?

Thanks for your help on this. Having a lot of fun so far building and expereimenting, but stuck on some very basic steps here I'm sure.