The float is probably stuck open.
The crankcase is full of gasoline. The reason for this is because of a problem with the needle in the carburetor. It allows gasoline to continue flowing into the combustion chamber even when the engine isn't running. An easy fix for this is to install a fuel shutoff valve in the fuel line close to the carburetor.
Kohler for sure
Hattiesburg, Miss. is the US factory for Kohler engines.
The float valve in the carburetor is not working properly. You will need to remove the carburetor and clean it or replace it.
Back fire can be caused by improper ignition or the wrong fuel air mixture. With the engine off remove the air cleaner and look below it. If there is fuel in the pipe then the carburetor is not stopping the flow of fuel and it needs a rebuild.
if it only backfires when shutting off, usually this means its getting to much gas!! if it backfires will running adjust carburater.
12-050-01: Available at most Lowe's
That depends on what size of Kohler engine you have ( my 149 cc Kohler engine on my lawn mower takes ( 20 ounces / 600 ml )
it is under the flywheel
No
The Kohler CV16S engine (including filter) holds 2 quarts of oil.
Your engine is getting too much gas. Either you have a problem in your carburetor or one of the cylinders is not firing and the gas is blowing right out the exhaust and being ignited in the muffler. While the engine is running use a rubber coated pair of pliers to remove one of the spark plug wires. Make sure you keep your hands on the rubber coating or you may receive a good shock. If it changes the sound of the engine and keeps running then both cylinders are firing and the problem is in the carburetor. If it does not change then you have other problems like a bad coil or internal engine problems. If it dies as soon as you remove the wire then put it back on and try the other one. The one that does NOT make it change or die is the problem one.