This carb or close variations are used on lots of small Mercury"s, not certain of the model #"s. . Within the carbureter bowl of the WMC type carbs which contain the primer. is a small red gasket, o ring, seat thingy. It is included in the carb repair and gasket kits. I have never found it necessary to replace one until now. A little tuff to remove, hell if I can install the replacement with out mangling it. Any tips on this ?