Craftsman Snowblower won't move (Cheap fix) 

Before putting your blower in the vertical position, take a piece of plastic bag (or zip lock bag) and put it under the gas cap and screw the cap over the plastic. The gas cap has a vent in it and if your gas tank is over half full, it will still drip even if it's screwed on tight. The plastic bag will seal it completely. Before putting the cover back on, wipe that metal drive plate down with alcohol or brake cleaner to get any grease or lube that may have got on it while you were working on it.

You could have a broken shear pin on the drive shaft beside the gears or a keyway that has broken or fallen out ! If you have the machine running with the bottom cover off and you lift the wheels off the floor and see what is happening ! Sometimes the shear pin or bolt is broken and it is still stuck in position so it looks like it is fine. You could also turn the shaft by hand with the wheels off the ground to see what is going on ! When you are done always use carb cleaner or varsol to wipe off any oil or excess grease on any belts or pulleys and the rubber drive wheel and then sand the drive plate ( The round metal plate ) And wipe it clean as well ! Everyone seems to think that all snowblowers have a transmission ( A few of them do and a most of them were made in China and I would not buy one of those ever because it will cost more than the machine is worth new if you are paying someone to do the job ) but most just have a simple system that drives forward in 5 or 6 gears and backwards in one or sometimes two gears ! Forward is on one side of the circle shaped disc and reverse is on the other side of centre . If you are going forward in reverse or not moving at all in some gears it could be because the adjustment is wrong meaning the rod is too long or too short ! At the top of the machine under the gear shift tou will see a removable clip that you can remove and then turn it clockwise or counterclockwise usually about one or two turns and then try it ! The only other problem you could have is maybe you only had one wheel with a shear pin and the other was free wheeling and the other wheel has a broken shear pin and the pin might have fallen out ! I work on them all the time and once you know what does what it is easy to figure it out !

Show us how to change the chain 😅

a briggs engine on a craftsman snowblower? wow, that must be OLD