I'm not really familiar with Polaris engines (I know better Rotax and reed intaked engines), but anyway.
Some time ago, my 125 was a pain to start, but seemed to run fairly well. I discovered my piston was "worn". -> check your compression
now, my 440 sled is a pain to start when the engine is warm. I think I found out that it is simply because all the powder gets in the engine compartment and finds a way in the carbs (I found water in the carbs). -> check your carb connections (and I would put an air filter on). -little message to Thor :yes, I think it's as stupid as that, no primer story or whatever...just snow/water under the hood.

You really need to look the plug. Actually it's first thing to give you a clue about what's happening. The machine won't start and the plug is dry? No gas. The plug is wet? Then you got gas, but doesn't seem to fire. Maybe your crankcase is full of gas (or too much fuel). shut the fuel line off, keep throttle wide open, and pull the starter rope (with the plug still off), do this at least 3 times, or until nothing comes out of he plug hole.
BEfore taking your mahine to a shop, tell us how your plug looks like. Then, and only then we will be able to give you some more precise clues.

Hope this helped/helps.

 

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I Had A Simalar Problem With My 99 TB.IWas Out Ridding The other Night And It Was Working Fine Until I Shut It Off.Then When I Tried To Start It Again It Wouldn't Start.I Also Had Some Spark But It Wasn't Very Much. When You Have The Spark Plug Out Does It Throw A Spark About A 1/2" When You Hold Away From The Head If It Doesn't And It Only Sparks When You Hold It Next To The Head It's Not Enough Spark. My Problem Was A Loose Wire For The Kill Switch. It Is Located Under The Headlight Pannel And You Will See A Little Black Box Mounted Next To The Oil Tank With 2 Wires Coming Out Of It With One Going To The Coil And The Other One Going To A Wire On The Left Hand Side Try Unpluging It And You Should Have All Kinds Of Spark. 99 TB With K&N And Clutch Kit Ride On!

 

I believe you have a choke problem. I had a '96 Scrambler 400 4x4 with similar problems, among other things. Try this....take the lid off your intake box and pull the filter out. Place your hand over the intake port with a small crack between your fingers to allow some air to go through then try the starter. I bet this works and if not it is a cheap way to ensure you are getting enough vacuum to pull the air/fuel mix into the carburetor. Good luck.

 

What's wrong with the starter? Did you put a new brush-plate in it?

 

My starter was broken so I was tring to start it everytime with the pull start. This weekend I installed a new brush kit and return spring and the starter worked great. I played with throtle cables and choke cables and it started a couple times I took it for a short ride came back and it wouldn't atart again. Plug had carbon on it but wasen't wet. I dont want to beleive that it is compression because I bought it new and really havent used it alot over the past years because it never was reliable so it has had limited use and its still runs strong when IT DOES RUN. I think its got to be a throtle or choke cable problem. I did put my finger over the plug hole and as far as I can tell with out a meter the compression feels alright. What do you think.

 

Well, if you're able to fiddle with the carb and get it running enough to ride then there's a good chance it's just a carb out of adjustment. Still I think you should give it a compression test just to rule that out. I had a similar problem and I thought I had good enough compression to start til I checked it and I only had 30 PSI. That told me it was a piston/ring problem. You should have at least 100 PSI to start. If you check the compression and it's good then you can be pretty sure it's a carb problem.

 

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I finally checked the compression this weekend and it shows 92 psi should I do a rebuild or is this enough compression where it should at least start.

 

The service manual says when you have starting problems to check the compression and it should read at least 100 PSI. If you don't replace the top end now it's just a matter of time. I wouldn't take the chance on damaging anything else by trying to put off redoing the top end.