1986 Other Suzuki Models Passing emissions, why are my CO le

Ok, I checked the oil 4days ago when I bought it, and it seemed to be pretty new, still transparent with little discolor. As far as power after the engine is warm...I'm assuming my power has been increased since I made the changes. The previous owner mentioned to me that he could drive 55 comfortably, and could top out at 60mph. Since the changes I made, I have been able to drive and top out at 70mph without any problem. Car seems to have the power it should have, but it has been almost 15yrs since I owned such an older carburated vehicle, so I really don't know how to base my assumption that I have sufficient power or not.

As far as the O2 sensor, I will check on that. Before I bought the vehicle, I ran a Carfax report, and it noted that the vehicle had failed emissions about 3 - 4 times consecutively in the late 90's and early 2000's. It also mentioned that before it finally passed in 2003, that the O2 sensor had been replaced, as well as the Spark plugs & Wires, Spark controls, PCV system repaired.

One more thing to note, and this may have something to do with the O2 sensor. I noticed when I bought the vehicle (Refer to pictures)

This bracket/ring was not even connected to the choke control or spring that regulates the choke, Somehow it had fallen off or became disconnected, leaving the choke on/open 100% all of the time. It was like this when I got it, and I am wondering if this was open all this time and not regulated, would it affect the O2 sensor in anyway?

I noticed this before my first test, but thought nothing of it...wasn't to familiar with the carb or parts, but after the 2nd emissions test that I did rather good on, I saw the round bracket below the assembly, brought it back up, seated it back into it's place and connected the spring. It was after this repair, and changing a vacuum valve that was faulty, that I went off the charts on my 3rd test. The vacuum valve that I replaced and the MCV (Mixture Control Valve) are between the air supply and carb. I didn't have to replace the MCV because I tested it after replacing the vaccum valve and it was working again.

Thanks for your quick response, and I will check the O2 sensor as soon as possible, but if the above mentioned makes any difference or points us in another direction, please let me know, and thanks again for your help.

As far as the carb being rebuilt...not quite sure, I fixed the choke problem I believe. The following are new pics of the carb, cold, and hasn't been started since yesterday. The choke is closed finally. Before I fixed the linkage it was always open. I did notice something on the carb as I was taking pictures. You'll notice in the first pic, I marked the rubber valve/plunger thing, if you look at the top arrow, you'll notice it is pointing at the very top of the plunger. It seems to be very brittle and torn/cracked. It seems to be leaking, and the plunger itself is wet on the outside, as well as on the carb body. I'm thinking I have just found my problem, but would like to be sure this might have anything to do with running rich or excessive fuel consumption. Thanks again for all your help. But then again, if this seal is broken,wouldn't this cause less fuel getting to the carb?