NormK,
Yes that is the choke thermal choke system.
But I need the engine numbers (Briggs standard setup of model and type) to look-up the appropriate service manual and IPL.
As if there is an air leak check that cross over intake tube, They are hard plastic and I have seen one with a hole on the back side but I still think you carb related problem but the off my head I don't remember carburetor setup the 550 uses and that why I need the model and type numbers,
