Here is my Here is my dilemma:
Please note: When pulling cord sled is always generating voltage(lights begin to light).

These parts are expensive I don't want to buy the wrong parts.

Snowmobile: 98xc 600, 4000 miles.

2/15 9 am, Zero degrees: started fine drove about 6 miles, died. Started a couple of times but would then just die. Tow #one

2/15 11:00am +10 degrees: Went to dealer and got the spec sheet to test the magneto, etc. Everything test fine, still no start.

2/15 4:00pm, +20 degrees: sled started and ran fine

2/15 9:00pm -10 degrees: 80 miles into ride. Died just like before no start. tow #2

2/16 9:00am -10 degrees: Started once then died shortly after. Would not run rest of day. All test still ok.

2/16 6:00pm +20 degrees. Would not start. Took off CDI took cdi into house and let warm. Installed on sled started first pull. Pulled into garage did not ride.

2/17 9:00 +10 degrees. Started right up seem to run on. Wiggled wires going to cdi and machine would die. tested all wire/connector to cdi all tested ok. Sled would start and die for a while then would not restart. Took cdi inside again to warm for 20 minutes, Installed and it started and ran fine.

Any advice would be greatly appreciated..
:
Please note: When pulling cord sled is always generating voltage(lights begin to light).

These parts are expensive I don't want to buy the wrong parts.

Snowmobile: 98xc 600, 4000 miles.

2/15 9 am, Zero degrees: started fine drove about 6 miles, died. Started a couple of times but would then just die. Tow #one

2/15 11:00am +10 degrees: Went to dealer and got the spec sheet to test the magneto, etc. Everything test fine, still no start.

2/15 4:00pm, +20 degrees: sled started and ran fine

2/15 9:00pm -10 degrees: 80 miles into ride. Died just like before no start. tow #2

2/16 9:00am -10 degrees: Started once then died shortly after. Would not run rest of day. All test still ok.

2/16 6:00pm +20 degrees. Would not start. Took off CDI took cdi into house and let warm. Installed on sled started first pull. Pulled into garage did not ride.

2/17 9:00 +10 degrees. Started right up seem to run on. Wiggled wires going to cdi and machine would die. tested all wire/connector to cdi all tested ok. Sled would start and die for a while then would not restart. Took cdi inside again to warm for 20 minutes, Installed and it started and ran fine.

Any advice would be greatly appreciated..

I would say the cdi is cooked. Maybe there is moisture in or something. Have you checked the compression of each cylinder. If you don't have a compression tester than just stick your thumb over each spark plug hole and pull it over to see if they both feel the same.

When your flying accross a field or down a trail and it's bumpy does the engine ever cut out at all, even for a split second. I am asking this as I have an 83 xc340 l/c and when I was flying accross the fields it would die for just a split a second and it is caused by a loose connection from the cdi to the coils.

Wow,
It's like deja vu all over again. I'm having similar problems with my 99 700XC with 5K miles. Tow tows down the mountain with the same symptoms. This last time at the shop it wouldn't start. Wiggled the wire leading to the coil from below the motor and it fire right up. I had some motor mount issues earlier this year, so I'm thinking one of the wires was pinched and is now shorting out.

I want my sled to work, the snow is perfect in Southern California!!!!!

That almost always is a toasted CDI. Last year we had 2 98 XC700's and one 97 in the shop at one time. Everything tested perfect, but they would all run for a while and then die. The one sled did it at exactly 11 miles every single time. 15-30 minute cool down and it would run perfect for another 11 miles. Weird stuff. All three sleds got new CDI's and worked flawlessly after that. They just seem to like to go for some reason.

I would make sure your connections are all good though, would hate to spend the money on something like that because of loose wires. It really sounds to me like the CDI is shot though.