<VV> Advice needed - loose throttle shaft

[chuck mckinley]

Friends,
	While attempting to finish my major tuneup today I discovered my engine
is basically idling only on the left carburetor, and tracing the problem
revealed that the throttle lever on the right carburetor is extremely
loose on the throttle shaft, to the point where even turning the idle
adjustment screw in as far as it will go, it doesn't actually open the
throttle. The throttle lever appears to be attached to the shaft by a
brass cap that looks a little like a TV screen, and I can't tell whether
it's pressed in, screwed in, or what. My questions are:

1. Is there a way to tighten this brass gadget to eliminate the rotation
of the throttle lever on the shaft? That would cure my problem. I tried
(very gently!) to twist it, in case it's screwed in, but I didn't want
to put much force on anything for fear of messing up the throttle shaft,
which appears to be quite sound. I also tried gently peening the brass
cap, but that accomplished nothing because I wasn't applying much
energy.

2. If I get a new throttle shaft from Clark's, I presume I'd still have
to remove the throttle lever and reinstall it on the new shaft, so in
any case I need to know how to get the lever off the shaft. I suspect I
could just grind off the little brass cap from the existing shaft, but I
hate to use such irreversible methods. 

3. I think a cheap trick might be to get a longer idle speed adjustment
screw that would allow me to screw it in farther than the stock screw,
but that seems like an irresponsible workaround that might lead to other
problems.

4. I've got a small welding set that I could use to braze the cap to the
throttle shaft, but that also seems like an unpardonable (and
irreversible) cheat.

I'm sure some of you have been through this exercise and know the
answer, so please advise!

Thanks,
Chuck McKinley
63 Monza 900 80 hp 3-speed