I've been having problems on and off with my Replicator 2 not extruding properly and getting jammed. The problem is somewhat intermittent, but definitely happens more often when starting a 3D print. I've been doing quite a few designs and prints of various quadcopter parts, which you can find on
A buddy pointed me to the following howto from MakerBot support:
My video demonstrates the process I went through to get my R2 extruding properly again. The only gotcha is that it is possible to tighten the plunger too much, which I what I initially did. If you over-tighten you'll hear a clicking sound, which I demonstrate at the end of the video. The solution was to loosen the set screw a bit and all is well.
Since I've gone through this process I haven't had any more extruder jams. Knocking on wood...