I agree that there is water in the carb's float bowl.
If you can't get to the drain screw, then try adding some water removal agent to the fresh gas.
I would use SeaFoam, which is also a fuel system cleaner and gasoline stablerizer.
Get SeaFoam at WalMart and most Auto Supply stores.
Remember that you will have to run the engine (at idle, I guess) to use fuel and get room for the
new fuel mixture to get into the float bowl.
Best if you can add the Seafoam and drain the float bowl.
Be sure to use the labeled amount of SeaFoam/gal of gas. More is not better.
Scoot Safely