Small Engines (Lawn Mowers, etc.): Carb flooding, snow pusher, carburetor kits

Question
We have a Scag snow pusher (a converted 36" mower with deck removed and their plow attachment installed) and it has the Briggs 18hp Vanguard engine on it. Runs like a champ, idles, throttles up and down, but then this: After I shut it off, fuel begins to POUR out of the carb from the butterfly/overflow. Of course, this drips right onto the exhaust piping and well.... So I replaced the carb with a NIB unit to no avail, then the fuel pump to the left of the carb as you face the engine from the air filter side. Still the same issue. What gives? From the looks of the carb and fuel pump, there MAY have been water ingestion but I can't be sure. The leak will continue until either I disconnect the inlet line or the tank runs dry. I'm quite mystified on this one.
Many thanks!

Answer
Hello James:

Have you Noticed that Over the Past 10 Years Most of the Push Mower have a Cut Off Valve? The Valve was Installed because there are Many of these Carburetors and Carburetor Kits that have a Needle that Does Not Seat Correctly and the Cut Off Valve has to be Turned Off when the Unit is Not Running to Stop this Problem. Is the Gas Tank Cap Venting the Tank Properly? If Pressure Builds in the Tank, it will Push Open the Carburetor Needle Valve and Cause this Problem. Since you have Installed a New Carburetor and are Still having this Problem; Install the Cut Off Valve at a Location that can be Easily Reached and Turn Off the Gas Flow whenever the Engine is Not Running. If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. Have a Happy Holiday Season and May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Comments and Ratings are Greatly Appreciated. Thanks.

Respectfully

John