That looks like the RIX that was EBAY'd out of Tampa. You got a real fair deal on it. I have the other one they had, which was a bit newer. So far, I have rebuilt the carburetor and the fuel pump for the motor. I have replaced all the valves and the associated o-rings, etc., in the heads. I will be replacing the piston rings, followers, etc,. on all the stages as soon as I can get those parts here from RIX. So far, mine pumps up to pressure fairly well, but as the pressure gets above 2500 psi on a 100cf+ fills, the motor will bog and quit. After I do the piston rebuilds, I will be looking at the intermediate pressures and then back at the Motor if the problem is not resolved.
So far with mine, I found that the 3rd stage head had a fair amount of corrosion, which cleaned up very well in the ultrasonic cleaner. The second stage was a lot better, and the 1st stage was immaculate as could be expected. Overall, not to bad for its age and what I invested in it.
I have a very nice Newer SA-6b that was converted to electric as my main personal compressor. I picked this one up because it was local and would make a fun project. I also figured it would be cool to have a portable gas driven RIX for road trips and as a back up for my main one. I have no regrets buying it, and am continuing to learn more and more about working on RIX SA's. They are very easy to work on, and RIX is very easy to deal with and very helpful.
Iain/hsm is definitely someone to listen to. I have followed a lot of his previous posts on RIX SA's and picked up quite a bit of info. I'd love to pick his brain for awhile sometime!!
Cheers, Walt