I have a 2001 Rubicon which turns over but won't start. I was using it, turned it off, and 10 minutes later when I went to start it, it backfired twice, and now just turns over. I can smell gas, but it doesn't catch at all. Does anyone have any suggestions of what it might be??

 

I had the exact same problem with my Grizz 3 days ago. Good luck, I haven't figured it out either.

 

see if you have spark, maybe the ignition module pooped out on it. or maybe the coil went bad too. The spark plug could be just fouled too. If it's wet when you pull it out, just spray it off with carb cleaner and dry it off with compressed air. Then see if you have spark, and if you do, put it back in and see if it will fire.

 

The back fire is one of two things...too lean or timing has changed.
Id go with the lean first. Drain the float bowl into a clean paper towel, or glass jar. Look for pieces of crud floating around or stuck to the paper towel. If you find crud/dirt/mud, the carbs gonna need a cleaning.
Most likely the pilot jet got a piece of crud blocking it. you could try starting it with full choke, or at 1/4 throttle...either of these will make up for a plugged pilot jet.
If it starts, but wont idle with the choke off...then the pilot jet is plugged.

 

Is your air filter plugged???? Causing flooding !! Remove your air filter and try to start it

 

keep it simple first. simply change out the plug and ensure you have spark. Went over to my BIL's place and he was about to tear into his AC 250. Since he's not very good at putting things back together I gave it a look. Plug was firing, just a little black, not overly bad looking. Pulled one (new)from my spare and put it in and it fired right up.