I have an old 1991 Arctic Cat Jag snowmobile. It was not running for a few years and the mice took over. Anyway, I cleaned out the entire fuel system and carburetor and managed to get it running again. It seemed to be running well. I took it to a lake for a ride and drove it about 1/2 mile or more at full speed when it just died on me. It does not seem to get any spark when pulling the rope. I have checked the fuel system again and everything seems fine and I also replaced the plugs with new ones but no change. Any advice on what to check next or what to try? Thanks

A Stupid answer, but check all kill switches, hope it is that easy.

Well all the switches are in correct position but I will have to start checking into the wiring I guess, which I really don't want to do. :)

Compression is likely good? now it is a matter of fuel and spark at the right time.

Compression is fine, just not getting the spark. I have checked the fuel line, carburetor, and spark plugs and everything seems to be working. Just can't figure it out now.

I have read there is a 4 pin plug connector, that can be unplugged and jump the brown to black and this bypasses all kill switches.

Could you explain that one a little better so I can try it? Can a kill switch just go bad like that on it's own? It really does seem like the kill switch is pushed in even though it's not. I get basically nothing when I give it a pull. I even tried some gas directly in the cylinders with new spark plugs but still nothing.

Then fuel is likely NOT the problem, I would say no spark, and Kill switches maybe the problem.
Kill switches usually work in one of 2 ways. Interrupt power, or Grounding of a wire.
One will be wired in series and the other in parallel.
Do you have a Shop Manual or Schematic? Good Investment.

The kill switch has two wires leading from it. I have disconnected the harness and direct wired it to bypass the kill switch but that didn't seem to help. I have also bypassed the ignition but that didn't seem to help either. Just can't seem to get a spark...

Do you have just the kill switch on handlebars and a Lanyard kill?

No lanyard. Just a kill switch by the throttle. The only thing running from the handlebars on that side are the throttle cable and two wires from the kill switch and those are what I tried to bypass.

You should be able to unplug or jump to work, if nether works, the problem is elsewhere.
Haven't found a schematic yet.
If the kill switch makes and breaks when switched as seen with a continuity/ohm meter, it is likely good and can be plugged back in.