I usually start it like this:
-Throttle at high idle, choke closed, flip until it pops.
-Throttle at high idle, choke open, 4 flips and it starts every time.
-If it's warm just one flip at idle and no choke.
It works like a clock.

The position of the sensor should be so the magnet is under it at 28 degrees before TDC. So it you're at TDC, then your magnet is 28 degrees to the left of the sensor as you face the plane from the front. I think I got that right but I'm not looking at the engine. You can down load a timing wheel here:
http://www.ch-ignitions.com/timing.html
http://www.ch-ignitions.com/imageEPQ.JPG

Just because the sensor is in a fixed position does not mean they mounted it correctly.