Outdoor Power Equipment and Small Engines - carb leaking fuel

I have this 8hp b&s mod # 190402 type051701 engine. I have taken it apart, cleaned every thing and all looks well. problem is the carb.I have taken this thing off at least 10 times and made adjustments to the float to try and stop the bowl from over flowing with fuel. i just spent $25 on a rebuild kit and still, cant stop the carb from over flowing. the gas is flowing to the airfilter, and leaking from underneith it.too much fuel goig to the carb is fauling the spark plug and the engine wont start.Im at the end of the rope and im out of ideas,need some help gents.

What all was included and replaced with the kit?
Apparently the needle and seat are not shutting off fuel supply. Possibly leaking float? Seat damaged?
The parts list for your carb lists 3 possible inlet valves (needle valve) depending on the code and if you have a fuel pump. Were more than one needle valve supplied with the kit?

If you can set the carb up to bench test the needle and seat to see if it indeed will shut off fuel supply, that would point to or eliminate the most likely parts.

the kit came complete with an idle,high speed and float needles, new main jet nozzle,and new gaskets.everything is new. the only thing i can think of is the float needle isnt seating all the way. the float is good.I dont know how to bench test a carb.

Basically just need to hook up a fuel line to the inlet as it normally would be. Then with the bowl off, operate the float and see if fuel starts and stops when the float is lowered and raised.
Might check the seat for the needle valve and make sure there is no corosion damage or debris.
How do you know the float is good?
It can have a pinhole in it and fill with fuel and not float. Shake it sometimes you can hear it slosh.