Hi George,

I think success tightening with an impact wrench depends a lot on experience. There are two methods for holding the crank while you use a torque wrench: a $50+ tool or two feet of clothesline to block the cylinder. I use the rope. If you search you'll find a good procedure written by Lucid. There are pitfalls to using an impact wrench others have run into, but mostly bonehead errors like tightening with the key out of place.

The tensioner is the suspect in the belt riding off center. Any timing belts that have failed for me have been stripped teeth at the crank sprocket, with a leaky cam and/or crank seal to blame for the lack of longevity.

BTW, on the bogging problem, I just gave my daughter's secondary ignition a bath in the dishwasher after noting I could make the problem appear with the hose nozzle turned on "mist" setting. She said it wouldn't pull out into traffic when it was raining pretty hard. Now I am repeating the misting, and not experiencing the bog while twisting the throttle spool. Will get her a new set of wires, cap, and plugs anyway.
--
Art Benstein near Baltimore

The taste of low quality lingers long after the satisfaction of low price.