Allow me to rephrase to see if I understand:
The original line has been modified to accept an inline fitting, with neopreme hose connecting the line to the inline filter and the inline filter to the fuel fitting on the carburetor?
If this is correct, then:
(A) Check to make sure brass fitting is correct thread both in type and pitch for airhorn.
(B) Unless the thread in both is tapered thread (pipe) then a gasket would be required to seat the fitting to the airhorn.
(C) Four hose clamps would be required (2 on each connector hose).
Jon.
