When i suck on the advance pipe the arm inside the distributor moves but then goes straight back down, as i am still sucking. I don't think its my sucking technique

Is the unit easy to come by, JK do a single advanced but mine has two pipes. I am looking at changing to Dells in the not too distant future so not sure if i will need the retard. I'm not sure the retard one from the weber 32/36 carb does anything anyway.