Inlet & Outlet pipes

[Ferrit]

I have a similar problem on a carb. I want to overhaul as a spare in that the return pipe has been broken flush with the carb. top. I have managed to carefully drill out the remaining stub and am left with a 6.5mm  diameter hole.There is enough metal to drill out to 9mm dia and use the fitting as described but what I have noticed is the original pipes internal diameter has a restriction in it, I have managed to get a 1mm drill in it.Presumably this has been done to restrict the fuel flow from the float chamber? Has the above modification been tried successfully?

found this one with the restriction fitted

https://ebay.io/m/JqpsyT

[Ferrit]

I had a very useful conversation with a guy from Webcon on the subject.  They are just around the corner from me so I popped in.  He gave me a few unions to try.  I have ordered the taps and will give it go tomorrow.  I dont see I have much to loose so worth a go.

He recommended Loctite 542 to seal threads and they use a small jet in the return union to maintain the c0.7~0.9mm restriction.  I will post pictures after I have completed the task :-)