Is it possible for sometime to freeze up in the shaft that is cause the motor not to start? It seems like there might be some resistance when trying to start. It was 19 degrees this morning.

If that's the case you probably need to replace your seals, maybe your bearings. There should not be water in the shaft...Grease doesn't freeze. I'd take a good look at things.

If the motor turns over but just won't start, that's not the problem though. It would have to have a shit load of water in the shaft to freeze and not allow the crankshaft to spin.

When it gets that cold, the grease doens't freeze but it is thick. Can make the motor turn over hard. What motor to you have? Had a 23hp that wouldn't start in the cold, soon as the sun hit it and warmed up would fire up on first turn. Had to replace the fuel pump, didn't have any problems after that.

The motor is a 23hp and after sitting in the sun for about 2 hours the motor fired right up. There is also a little bolt about halfway up the shaft and I just took it off and water came out. What does this mean?

Yes, that is very bad!! THere shouldn't be any water in your shaft. You need to replace your seals, and maybe your shaft if its rusted.