Please post pictures or links to pics showing the alignment problem. loger

There are steel-wire belt guides, 2 of them on a Tecumseh, that keep the belt from jumping off the top pulley. Maybe you have too much slack in the belt or don't have the top guides adjusted properly.

Purple: (I assume in the face ) lol , as Bay has advised the tension is normally the key alignment is normally preset , unless you have a bearing issue causing run-out of the pulley which can cause belt wear and eventually cause it to jump off .

I know the metal guides that you are refering to. This snowblower only uses the belt cover to keep it on the drive pulley. I was surprised to see no metal guides when I puled the cover.
Belt seems to be jumping off the big auger pulley and not the engine drive pulley anyway.

The pulley (mis)alignment is just a subtle offset that is noticeable when looking straight down over pulleys. Maybe only 1/4 inch or so. Like I stated, there seems to be no way of shimming either pulley. Maybe if I loosen bolts on engine mount I can slide the engine that little bit.

I can't get the new replacement belts to work for very long. The belts keep coming off. I see the alignment is about a 1/4 of an inch off with the large auger pulley being to close to the engine. I separated the auger body, 3 bolts on each side of the machine and added a 1/4 inch wide large sized nut as a spacer for a shim. I bought a car belt 3L350 with no cog like the original belt I had and my test run was fine. Big storm tonight for a bigger test. Current conclusion: Bad alignment will throw the new belts and/or the new cog belts are no good.

This post was edited by JustFixit on Fri, Mar 8, 13 at 18:10

The belt stayed on fine after snow blowing a 9in snow storm. Well, until I tried to snow blow the newspaper, but that's another story! Not to bad, delay of game 15min.