A snowthrower is not that unreliable, at least if you go through it every few years and make sure it's up to the task. Here are the basic steps I follow:
The two bearings for the auger are readily available and low cost, so just replace them if they are at all worn. While the auger is out of the main housing, straighten any bent flights and weld up any cracked areas. Clean up any rust on the inside of the auger housing with a wire cup brush and/or sanding disc on an angle grinder. Put a fresh coat of paint on the auger housing and when that's set up put on at least two coats of a brush-on graphite paint like Slip-Plate. remove and inspect the cutting bar, reverse it if overly worn on the front edge or replace it if it's already been reversed. Inspect the runners, reverse, replace or weld on skis as needed or preferred. Remove the discharge chute and clean it up to remove any rust, then repaint and coat the inside with the same brush-on graphite paint, also coat the area where the discharge chute rotates,
CLICK HERE FOR MORE DETAIL. Inspect and replace if needed, the two needle bearings on the chain tensioner/drive shaft, these are easily replaced. I used a socket to drive the old ones out and the new ones in, be sure to line up the hole in the bearing with the grease Zerk. While you have this assembly apart inspect the chain drive sprocket, replace if overly worn. With the drive-shaft U-Joint bearings, replace if necessary. Open up the gear box and remove the lube, inspect the gears and bearings, replace if needed, refill with fresh lube and install the cover with a new gasket. Make sure the drive pulley is properly aligned with the PTO pulley. Inspect the drive belt, replace if cracked or overly worn. Install the auger and put it all back together and adjust the chain tension. Inspect the auger rotator, adjust as needed. If the little U-Joint for the auger rotator is worn out
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This was a heavy wet snowfall from March 2006 with my #2 125, which at the time had a worn out underpowered K301 in it, running a properly maintained and setup QA42. That 125 now has a rebuilt K301 "Killer Kohler" in it and it really makes that QA42 throw snow.