Re: popping and spitting.....
Backfiring type pop?
Did the sled idle for abit before you loaded it on the trailer, or did you run at low speed for a bit back to the house. It could just be that it's all loaded up, or a slightly flooded condition from low speed/idle conditions. Change the plugs, tear it across a field a few times and see what happens. Mine got all loaded up one night last week. I had ridden it down a hill and across a field. Probably a 1/4 mile. then i shut it off. When i restarted it ran on two cylinders, popping etc. the next night, I changed a couple plugs, and it stayed that way for 4 1/2 miles then finally came out of it.
Not all do it but many sleds have an issue with flooding on the trailer. Shut the gas off before you trailer (not that this is your current issue). The jostling causes fuel to slosh/trickle out of the bowl and down into the base. This floods the base after awhile. and if you got a full tank sloshing around gravity only helps this process. It took us 4 hours to start my dad's XLT one day. We took the base drains out, and the fuel just poured out. Just an FYI.