Got all the rivets out but I doubt if you will approve of my technique. I realized that it doesn't take much force to move a rivet, so I cut down a simple hook carefully put it behind the rivets. They popped out like a champagne cork with almost no effort.
But when I took out this one I noticed the rivet in my kit is a little bigger than the original. I might be able to reuse the old one. It came out very clean and seems to be a bit of a press fit to it. Or I could ram home the bigger rivet. The opening seems like it is a little deformed and close to the edge of the casting.
Thoughts? Of course the last rivet stays where it is.
I salute your ingenuity. I applaud your willingness to take the job on. There are two rules in rivet removal: Don't lose it in the passage and don't damage any threads. The angle of your second photo threw me for a moment. Look at the pic below. OH, CRAP! is an appropriate response. There is one fix for this. When you put the old rivet back in there, apply a good coat of Loc-Tite Red all around the shank and under the cap. It must be completely sealed. Do not try to alter the outward appearance of the cap until it is sealed/cured and secure in the hole. Soak up the excess sealer with a paper towel. Give it 24 hours to cure. Say a little prayer. There is hope.
I think I can reseat it as you suggest. I have to get the nozzle out yet and then I can finish cleaning it and blowing it out. Haven't had the time to get the appropriate tap. I will PM you about sending you the throttle rod and body for bushing service. I like doing things myself --that's part of the fun--but I'm not going to tackle that job. It seems to have a lot of play in it.