You pull the key out of the assembly, get a degree wheel, and rotate the magneto 7 degrees counter-clockwise while looking at the front.

That will advance it from 28* up to 35*. Better have a Dynotron starter or a really thick leather glove the first time you grab hold of that sucker. I got a 54cc chainsaw conversion up to about 35* once with a C&H ignition. I was moving my timing ring around and trying to "static" time it by starting and taching, then advancing a bit more. It smacked the heck out of my hand, first time I flipped it. I was doubled over and dancing around in the driveway with my hand between my knees and screaming for my mommy. [:@]

Next day, I went back after it with my degree wheel and realized my stupidity. 35* was just a teeeeensy bit too much for that engine. Better be carefull with that Quadra.