Okay gang, I need some "fine tuning" tips here.
When this is up on blocks, and running in reverse, it runs perfectly. Here is a picture how how the worm sits when in "reverse" mode:
You can see there's just a very slight gap between the brass frame and the washer/worm. The entire shaft: worm, armature, etc. turns smoothly with almost zero fore and aft movement. Perfect. 
Here is the gap when polarity is reversed, for running "forward":
Although not much greater, I think that gap is now enough to throw the worm too far back towards the rear of the engine; this (I think) is what's causing a "hitch" (both visible and audible) in the mechanism. The shaft now moves fore and aft by as much as a 32nd(?)
I cannot detect any other reason for this "hitch". I don't think that adding a very thin additional washer would help, as that would cause a bind when in reverse...maybe.
There is not a whole lot of adjustments available with the way this is designed; I thought that maybe I could tweek the big brass "arm", and maybe move everything slightly forward, but I just don't see how that could done, and even then help much.
Speaking of "help":..HELP! 
Mark in Oregon
