Weird S-200 carb
I bought a "broken" Toro S-200 for $20 to repair and sell for a profit when the first big snow hits. The guy said it wouldn't run and my experience with the S620 I bought told me it probably just needed attention to the carb. Sure enough the diaphragm was petrified, so I disassembled, soaked in a gunk pail for 24 hours, blew out and started rebuilding. I noticed the main adjustment screw was missing and the weird thing about this carb is that the hole where it goes isn't even threaded and there's what seems to be a welch plug way down in the bottom. I uploaded a pic. I've never seen this before... all of the exploded views I've seen of this show both screws. I don't see any other adjustments on the carb, it's otherwise exactly like the usual 200-620 Tecumseh carbs. Possible this style of carb was used on other applications and this carb came from something different, like a pump engine or similar? I'm not sure if this will be ok or if it's gonna cause problems.
My ex brother-in-law has an S200 with the same single screw carb. I put a kit in it a few years ago and it still runs good, for what it is. The motor is a fixed throttle, so just adjust the screw for best running.
Toro 8/24 (38080) 1989
Toro 721-QZR (38743) 2015 (Hemi Predator Power)
Toro (51984) Hand Held Blower (For the light stuff)
Experience is something you don't get until just after you need it.
Likely is was a way to comply with the EPA mandate of no adjustable carbs without needing to make new molds for carb bodies. Fit a fixed jet, drive a plug behind it and done . . .