Small Engines (Lawn Mowers, etc.): carburater shut off valve, carburetor, air filter

Question
Hello John

Followed your advice and installed a fuel shut-off valve to correct the ongoing leak through air filter even after changing needle and seat twice.Problem is now solved.I wonder however since the leak was substantial,( it would empty the tank)if when the engine is running,and the shut-off valve open of course if too much fuel is supplied to engine making it run rich.The needle is obviously not doing what it is intended to do, so wouldn't more fuel than needed by engine flow into the bowl and then into venturi?

Thank you so much for your help.
Sincerely
Casimiro

Answer
 Hello Casimiro:

 If the Carburetor is Running Rich you will See Black Smoke from the Exhaust. You May need to Look Into a New Carburetor. From your Description it Sounds like the Molded Seat for the Needle is Pitted. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks. Be Safe.

 Good Luck

 Respectfully

 John