The float valve is not cutting off the fuel.
The fuel level rises then overflows through the bowl vent ( which now has to be inside the carb ) .
This fuel flows down the manifold and fills the cylinder , trickles past the rings &e ends up in the sump.
So first problem is to fix the carb.
crank the engine without the float bowl on & hold the float up so it is horizontal.
In this position it should stop the fuel flow.
If you have to push it up any higher then the needle &/or seat requires replacing.
Check the carb gasket, some times they overhang the edge and foul on the float, preventing it from rising high enough to stop the fuel supply.
Double check the pushrods it is possible to cross them over and also possible to have the pushrod sitting on the edge of the cam follower not in it.
Both valves should sit at the same height and both cylinders should be the same.
Change the oil.
When it is running, change the oil after about 1/2 hour and the oil filter as fuel diluted oil will damage the engine.
If the oil is too thin you can not get enough compression in the cylinder for the engine to fire.