even though theres flow it may not be enough pressure to run the machine
and youll get some flow with the o-ring in there where its not supposed to be
ive gone to calls where they had 2 get stuck in there lol
the minimum inlet pressure for the vaporizer to work is 30psi
when all is right the normal pressure is about 60 - 90psi on the high pressure side

the outlet pressure is 1.5psi (theres a 1/4" pipe plug on the back you can hook up a fuel pressure test gauge to) not too much over 2psi and it wont run (dont try to test the pressure on the high pressure side AND be super careful on the low side the vapor is VERYYYYYYYYYYY flamable lol)

also check your fuel lock off
it might be vacuum controlled (this will be around the size of the model J but with a line into it from the tank and a line out to the vaporizer + a vacuum line from the carb, make sure the vac line didnt fall off either or is loose)

or its controlled by an electric shutoff solenoid
check the wires to it

try not to blast propane jets into open air from disconnected propane lines
this is a good way to cause an explosion lol (overhead heaters etc)