Small Engines (Lawn Mowers, etc.): Briggs & Stratton Carburetor, briggs stratton, hp model

Question
I have gas getting into the crankcase.  I have rebuilt the carb but still get
flooding mainly when engine is off.  I notice the rubber seat is loose in the
brass seat and will fall out of the brass seat easily.
1) Should the rubber seat fit tight in the brass seat?
2) Can the brass seat be replace on this carb?
3) How is the brass seat replaced?

Briggs & Stratton 8 HP
Model 190707
Type 2518-01
Code 88052510
Carburetor Overhaul Kit 394698 (brass seat not included, only rubber seat)  

Answer
I can help you after I did some research but, it's rather complicated...send me your email address, and I'll furnish you with my shop phone number and explain it to you ......If I just put the shop number up here everyone and their mom will be calling me.
Better yet you'll never get back to me I'll be maxed out...so send me your phone number to my email I'll check through the day and when I get it phone you..   smallengine@woh.rr.com      Tom