Ski-Doo is a brand name of snowmobile manufactured by Bombardier Recreational Products. The Ski-Doo personal snowmobile brand is so iconic, especially in Canada, that it was listed in 17th place on the CBC's The Greatest Canadian Invention list in 2007. Ski-Doo also has its own range of snowmobile suits.

Snowmobile Troubleshooting

Quick Fixes
The good news is that many of the minor issues you may experience can be solved with a series of quick fixes. It’s easy to get frustrated and start taking your machine apart piece by piece. Before you do that, you’ll want to try some of these snowmobile troubleshooting tips.
For example, check to see if you accidentally hit the emergency off switch. Is your machine low on fuel? These might seem obvious, but you’d be surprised how often these things are overlooked. If the gas in your tank is leftover from the previous season, it’s not going to be any good. Drain your fuel tank and replace it with fresh gas. Confirm your machine has plenty of coolants as well. Tighten any loose nuts and bolts on the head gasket. All of your wires should be properly connected. Any of these minor details could be the reason you’re having issues. Give them a shot before you move on.

Flooded Engine
You can flood your engine if you over-choke or over-prime it. If so, you’ll notice the smell of gas or see it coming out of the exhaust pipe. It will eventually evaporate so you can start the engine. However, if you need to ride right away and don’t want to wait in the cold, there’s more you can do. Clear the line by hitting the kill switch and pulling the spark plugs. Next, hold the throttle open and pull the starter cord to clear the line. You may need to pull the cord quite a few times to clear the line. Clean off the spark plugs and replace them.

Dried Out Fuel Lines/Carburetor
On the other end of this spectrum are your fuel lines and carburetor, which may have dried out. This is a common problem that occurs when your machine has not been used for a while. In some cases, you can correct this by using a carburetor cleaner or starter fluid. Keep in mind that if the problem is more severe, like the combustion chamber not receiving fuel, you may need to have the carburetor cleaned or possibly rebuilt depending on the severity.

Worn Out Spark Plugs
You can check the condition of your spark plugs by removing them and grounding them on a head bolt. When the engine turns over, a spark should be visible. If there’s no spark or it appears to be weak, that’s a sign that your spark plugs need to be changed.
If your spark plugs seem to be working fine or you’ve replaced them but your snowmobile engine still won’t turn over, there could be a bigger problem with the electrical system. Check some of the key components, including the plug caps, coils and wires, the charging discharge ignition box, and the regulator.

Low Compression
Finally, if you’ve observed that your snowmobile isn’t as powerful as it used to be and you’ve ruled out the above issues, low compression could be the problem. You can perform a compression test on each cylinder in the engine. Generally speaking, the optimal compression is 120 pounds per square inch (psi) or higher. Anything below 110 psi could indicate a possible problem. Most engines won’t run on anything lower than 100 psi compression. 
Be sure to confirm the compression is the same in all cylinders. If one or all of them is low, the problem could be scored pistons or cylinders, worn-out piston rings, a damaged crank seal, or a defective head gasket. You’ll want to check all of these possibilities before you bring your machine in for service.

SOURCE: https://www.yellowstoneadventures.com/blog/snowmobile-troubleshooting-guide