Flooded Motor on 600 RMK

I have a 1999 RMK 600 with a bunch of miles on it. I keep it as an extra sled for when family or friends want to do some easy riding. I prepped it out a couple of weeks ago for an upcoming ride. Started fine after a long summer hibernating (left gas turned on too when I was done, as I do on all my sled in season). I tried to start it yesterday to put it on the trailer and the engine was so flooded it wouldn't turn over (hydrolocked). Pulled the plugs and turned the engine over a bunch. Once the majority of the gas was expelled through the plugs holes, put the plugs back in and it started fine, then turned the gas off. Went out a gave it a pull today and it started like normal.

I have a few thoughts on the possible problem:

1) I left the back end jacked up after test running the track two weeks ago.
Would this cause fuel to gravity feed into the engine?

2) I had an old Trail 440 with a similar problem several years ago.
The diaphram went bad in the fuel pump resulting in fuel being sucked into the bottom end of the engine. Could this be the same problem?

3) I had placed a board between this sled and a sled next to it to keep a tarp placed over them from sagging into the gap between them so train water wouldn't collect. It is possible the board pushed against the throttle lever.
Would this cause this much flooding?

Has any body experienced something similar?

Heading out for a ride in eastern Oregon tomorrow and don't want to end up towing this sled back in off the trail. I am thinking of picking up a spare fuel pump just incase.