Snowmobile Repair: snowmobile engine wont start, compression tester, skandic

Question
Scandic skidoo. Was working fine, put in new plugs, ran on a 74 mile trip. When off loading from trailer backfired a few times. Drove to put away. Now won't start. Getting spark-seems to be flooding out. Won't fire at all. Plenty of compression when pull on cord. Has electric start as well. Plugs full of fuel when I take them out-even with no choking.
1998 Skandic Skidoo.

Thank you for your time.

Answer
Hello Kathy,

  Sounds like the inlet needles are sticking in the carbs. Your best bet would be to purchase new Mikuni inlet needles and seats from http://216.37.204.202/Skidoo_OEM/Skidoo.asp  .  Also, be sure to install new spark plugs when attempting to start the sled again. Another thing you may really want to look into is the compression on all cylinders. The most likely possibility is that the sled lost compression. Testing the compression with a compression tester is ideal. Other than that, you can always turn the key switch off, remove the plugs, and have a helper crank the engine over with the pull cord while you put your thumb on the plug hole. The compression should force your thumb off of the hole. Repeat this step with the other plug hole. If there is a lack of compression, the sled will need an engine overhaul. I hope this helps you. Let me know if you have any other questions. Good luck with the sled! --Arcticatman