Briggs and Stratton Cast Iron 14hp Won't Start. Nothing I've seen before!

Hello I have a Briggs and Stratton 14hp 32000 in a Simplicity 7014. Freshly rebuilt. The engine ran PERFECTLY until one day it did not want to start. I eventually got it started and it ran perfect. Once it was ran and drove for a while I parked it to see if it would start back up. It fired immediately and so I shut it off and tried it again. Same result. I parked it confidently thinking it was just a little dirt in the carb or an other problem that was pretty much fixed. I let is sit for a while and during this period it rained. I did not think much of it till I went back out there to start it and it would not start. It would fire once and a while, but would not start. Even spraying carb cleaner down the carb did not make it start. I figured it was water in the carb and tank from the rain and pulled it in the shop to fix. I drained the tank and replaced the carb ( Yes I do know I could of cleaned it out, but it needed one anyway) and the exact same problem occurred if not worse. It would pop a little with fuel in the carb, but would not start. I checked spark at the plug, it has good compression, the air filter is off so no restriction there. When I pulled off the fuel line fuel immediately started pouring out as it is gravity fed. I even checked the points and they were at 20 thousands. The only thing I can think of is the flywheel key sheared and the timing is just slightly off. Although it started just fine when I went to park it and it restarted well immediately after. I am fresh out of tricks and ideas. Any idea of what it could be before I take the engine out and check the flywheel key? Thanks and have a great day!