RE: WYK Walbros, 40cc Briggs
Like I said, if it has a spring in the fuel pump for the diaphram, it will pump. If not, just add one.
A two stroke has a positive and a negative pulse to operate a fuel pump. A four stroke only has a "negative" pulse if it is operating off of the intact tract. It needs the spring to move the fuel pump diaphram in the opposite direction after each unidirectional pulse.
AV8TOR