Mike - just found this thread and see you just picked up your QA42A. I loved using mine on my 1450 when I lived in CT.
Kraig - Oh Great One - Keeper of the Photos - how bout posting those 3 pics of me throwing snow on my driveway. If I recall correctly they were from a March snow storm and the snow was really heavy and wet, but the thrower still did a great job.
Mike, there are alot of things to look over on the thrower. I wouldn't worry about the finger guards in the chute which you mentioned. They actually tend to attract the snow so you will want to put your fingers there and you are NOT supposed to anyway. But you should NEVER leave the tractor seat with the thrower running anyway. As for what to really look for, I see Charlie mentioned the little drive sprocket and drive shaft. That can be a problem area. I really recommend tearing the whole unit down and doing a thorough inspection of everything and a reasonable restoration if you have the time before snow. The paint needs to be good or you will have some trouble with snow sticking. Slip Plate (graphite) paint is good but I never used it myself since I didn't care for the color or that it does wear off over time, more so than good paint. All the mechanical things are just as important if not more so than the paint. That small chain sprocket tends moves slide side to side in the holder it's mounted in, and I always liked shimming it up with brass shims to keep the chain aligned with the main drive sprocket on the auger (It slides side to side as you raise and lower the thrower and puts pressure on it). Also, allowing it to slide side to side causes it to "cut" into the mount where the needle bearing are located, and it can wear right thru the casting holding them in place, but I think Charlie sells those parts if you need them. Also, I restored at least 6 of these units over the time I lived in snow country, and everyone I picked up had the set screws loose on the drive shaft. This can really mess up the keyway and shafts it mounts to (the small sprocket shaft and one of the gear box shafts). If either is bad you can probably get a new keyway cut into them rather than replacing the shafts themselves. Do to the age of the thrower I believe it's a good idea to disassemble the right angle gear box and make sure the bearing, shafts, keyways and both gears are good. Of the units I went thru I only ever had a couple bad bearings which is suprising since the outer bearings don't really get greased from the gear box operation - which is also why I like using the FAQ recommended 75% gease and 25% oil when refilling the box. It's hard to describe how the box itself is designed but you'll see when you disassemble it (an inner and outer bearing for each shaft). The auger can get really worn down if the chain is not kept properly tensioned but it can be replaced as well. The chain itself needs to be in good condition, not all froze and rusted up. The bearings on the auger are really hard to check without disassembly. You can tell pretty good how they are when you have the chain removed. They are pretty easily replaced (it's the same bearing lock used on the mechanical PTOs on the front of the tractors). They are not expensive and are not greasable so I always replace them. About the only other thing mechanical is the gear wheel for rotating the chute. These can get sticky and rusty on the inside shaft so I always disassemble and clean them good, greeze'm up and reassemble. When you remount the gear wheel assembly make sure you take a little extra time aligning it - otherwise when you try to rotate the chute it wil jam in the chute holes. Good luck and have fun throwing snow. I always loved it}