One can also use a bit of starting fluid in the intake with a machine that's hard to start. It may not be an everyday approved method, but really helps lighting off.
94 440 prowler tuff too start
You have to start with the basics to narrow things down. Start with gas, compression, and spark.
A sled with low compression will be a bear to start. Both cylinders should be within 5 to 10% of each other. Compression is the easiest thing to check. If that checks out move onto fuel. Bad gas?
Once your sled is running does she run good, or stutter and hesitate a bit? Try some fresh fuel and a full can Sea Foam. You could have moisture in your fuel, or dirty injectors. Sea Foam should help either of these. How is your fuel pressure, may have an issue with your regulator - pretty common problem.