Rotax 277 help!

Hello everyone from Maine. 

I need some assistance with my Rotax 277 in my 1981 moto ski mirage 1 snowmobile. It was my grandfather’s sled. He gave to me before he died so it has alot of sentimental to me. I like to use it with my kids. 

So a little background info. A couple years ago I lost spark. Ended up being the condenser. So new condenser and points. FIXED. 

This year I go out, no spark. I tear it apart  it was like the points weren't working. So I cleaned points and reset. SPARK.

Mouse built a nest in air box and exhaust. Cleaned those out. 
I also cleaned the carb.

new pump rebuild kit in the Mikuni fuel pump.

no fire, no kick, no anything. i even put a little fuel down the cylinder and down the carb. The sled will not fire, it won’t even kick at all.

i checked the compression. If my gage is accurate it’s saying I have 90 psi.   

i Don’t know what to do! 

could crank seals cause all this? 
topend? Me fiddling with the points cause this? Not sparking at the right time? I DID NOT move the stator plate.

 thank you

George