Small Engines (Lawn Mowers, etc.): Briggs 17hp Intek Carburetor problems, walbro carburetor, carburetor problems

Question
I have a Briggs Model 311777 Type 0143 e1 Code 990115zd that has a Walbro Carburetor with LMT 154. I have rebuilt this Carburetor twice, both times with Briggs parts and it still floods the engine. I also bought another one that is identical (lmt154) and it is doing the same thing. Only part I haven't replaced in them is the brass needle seat. I rebuilt many Briggs carburetors, but never had to replace the needle seat. Is that my problem, or is it something else? I know how to remove the needle seat, but how do I know when its installed correctly?

Thank you,
Sam

Answer
SAM

The manual says this
6. Using Knockout Pin #19135, press new
fuel inlet seat (A, Figure 51) until flush with
fuel inlet boss (B).

One thing if it is not installed correctly the float will be low, not allowing enough fuel into bowl if seat is not down and it can leak. The hole the seat goes down is too large, doesn't seal seat until the last little bit where the hole has a ridge that narrows up the hole. This allows some wiggle room the the needle so it doesn't hang.Place a drop of motor oil on the seat before placing in the hole, makes it easier to go past the ridge and make sure to press all the way down. I've always used a "T" handle allen wrench, gives you a nice palm surface to press the seat in.