It is the stop screw for the idle. Yep, I already paid for it! It was only $5, but still!

Thanks for the info I was looking a photo of the screw up close and it seems like there is some fancy notch work on the threads...maybe not...

Well, I will try to take a look at it later and see if I can get something to work. Unfortunately, Horizon doesn't carry any MDS stuff anymore. I called them and they said some engine company in the Midwest US was stocking their parts, but they couldn't find the name or phone number. I tried Googling for a long time with no results!

Thanks,
Garret