Ariens 42 inch 93604600/A 175BG42

My mower has the 17.5 hp briggs and stratton engine. I went to start it for mowing season, and it would run for about 30 to 60 seconds and emit white smoke, then immediately shut down. I gave up and went to try again the next day, only to find out, that my fuel tank was completely empty. I added more fuel, tried to start it, and I got fuel out of the exhaust. I looked into the carb and the bowl was full of gas. I pulled the plug and fuel came out when I rotated the fly wheel. I pulled the muffler and same thing, fuel in the exhaust. I drained the engine oil and it was full of fuel also.
I had a buddy rebuild my carb he said my float was stuck.
I put the carb back on added fuel, and cranked it over. The mower started and ran beautifully for all of about 5 minutes. Then it puffed large plume of smoke and some thick engine oil mixture then shut down.
Now my mower won't start at all. I can't spin the fly wheel by hand like I did before. When I crank it over, the starter just clicks and tries to spin but it won't spin. I tried to spin the head by a large socket wrench thinking maybe it was binding up. The head does spin for about 3/4 of a turn then sort of binds up even with the wrench.
I'm at a loss of what to do next. A buddy said something about being compression locked but I don't have a compression checker.