The float is probably stuck open.
Kohler for sure
no, but there is an inline filter.
Hattiesburg, Miss. is the US factory for Kohler engines.
Yes, it charges from the magneto.
12-050-01: Available at most Lowe's
According to Wikipedia, a magneto starter, also called the ignition magneto, provides current or pulses for the ignition system of a spark-ignition engine, like fuel engines.
That depends on what size of Kohler engine you have ( my 149 cc Kohler engine on my lawn mower takes ( 20 ounces / 600 ml )
if it only backfires when shutting off, usually this means its getting to much gas!! if it backfires will running adjust carburater.
Basically the second Magneto is provided as a fail safe. There are a lot of redundancies in aviation, especially when it comes to maintenance and safety. The second magneto on a single engine plane is there to contine to provide a spark to the engine in case of a failure of the first magneto.
If the P-lead is grounded, the magneto doesn't generate spark. Basically it turns the engine on and off.