Almost sounds like the engine is flooded and has one or two plugs firing, but not able to crank it over. Check the plugs and see if they are wet.
The way most people were interpreting it, the engine would not crank at all. That is what I thought when I first read your post. Engine turns but will not start. Correct? How can you check the timing with a gun if it is not running? Hummmm.
Ed