I know these sleds have a few common issues but I don't know very much about them to help you. So i am not going elaborate on any of them. Hopefully it is none of them. hopefully someone who knows will chime in and get you going.
I think the spark looks good. I am assuming you have compression and fuel. along with clean carbs.
Have you sprayed starting fluid around the crank seals, head gasket, carb boots and stuff to check for leaks?? Did the tank have any old fuel in it?? If so did you get it all cleaned out?? Water in the fuel/bad gas is the only other thing I can think of.
In Iowa we have both at the gas station just have to pay a little more for the ethanol free. The first time it took me a little bit to figure this one out because everything moved freely excepted that little pin under there. Very easy to over look. It doesn't move much. I thought something really bad happened to my sled and let it sit for week because I did not want to know what was wrong. So this year when I cleaned my carbs I made sure it moved freely.