The floats sticking in the open position in the fuel reservoir. Possible, but this linkage almost never distorts. Another possibility is a pinhole in the float, especially if the float is hollow soldered metal. Most likely is a worn out needle valve and/or seat. These are included in most carb rebuild kits. After replacing, check the float height against the specs, usually also included with kit.
leaking or cracked manifold
It is probably a vacuum leak. that model doesnt have a carburetor, it has fuel injection. and whining is usually a vacuum leak. it also might cause the engine to "lope" at idle or for it to "surge" when you hold the accelerator steady.
Yes it could if you in fact have a carburetor. Carburetors were fazed out during the 1980's.
if the the river overflows it wont cause any harm by Craig mac
A misfire will cause flames to come out of the carburettor
Most likely, Your float is stuck in the carburetor. If it is stuck open gas will continue to flow into the carburetor bowl, then it will flow into the crank case and cause your oil level to rise. You need to take off your carburetor and adjust the float.
a carbureator cause there easier to fix
Yes
Regulate the carburetor and replace its gasket.
Lots of things
You need to adjust your carburetor.
A Briggs and Stratton L head twin engine wills pit gas out of the carburetor and flood out when starting if the diaphragm has been damaged. This will cause excessive fuel to enter the carburetor.