'97 Teleflex (Seastar) Throttle control teardown?

The throttle has always been a little 'jerky' when you first move the throttle (after going into gear).  Not a problem pulling a skier in the course, but a pain when trying to teach someone to ski or get up on a wakeboard when you need really precise throttle control at low RPMs.  I replaced all cables when I got the boat 2.5 years ago, but the throttle wasn't any better, so a few months ago I replaced the throttle cable again with a larger diameter heavy duty one (that was supposed to make it smoother).  It helped a little, but still an issue.  No binding at the throttle body and no issue/problems with Perfect Pass.

In the past, I greased as much of the control as I could reach from underneath, but it still has a little hesitancy.  I'm in the process of dismantling it and am stuck with how to dismantle it further.  There's a spot on one of the sliding pieces where the metal is a little rough which I can sand smooth , but the real hesitancy is in the actual throttle shaft.

I looked at NautiqueParts and it's $400 for a new one, but I think it only needs lubrication internally.  My '96 had 1,600hrs when I sold it and it worked a lot smoother than this one (I'm at 1,110 put 200hrs on it at our course site).

Has anyone been able to tear into here and pull/grease this shaft?  This is where I think I need grease.  It doesn't look like a normal ring clamp, and I also see a pin that would have to be removed, and I don't see how that is possible since there are no slots or holes that would allow the pin to come out.

The unit is riveted closed, so I'm wondering if this is as far as I'm going to get.  If so, I guess I'll just have to get a new one (I'm anal about things working like new...).

Any suggestions (besides not telling my wife and spend another $460 ($400 plus shipping and tax) on this project?

Thanks,

Gordon

    Are you gettting the jerky feeling in the throttle with the cables disconnected? As I said inthe PM I did not drill out the rivets. I did have issues with the brass connectors that I replaced, and if you do not get the cotter key bent correctly The new brass parts were too long and caused binding, so I went back to the old ones and everything was fine. 

  Here are some pictures. I had these posted back in 2018 when this happened but they got lost in the hack of the site. 

Original

New on the left, old on the right. 

New installed but too long, hits other arm and jams. 

Here is their video on Morse throttle.  Might gleam a little something from it.   https://youtu.be/9KNzQxpAeE4