Tillotson X question

[Geezerville]

I am rebuilding a few Tillotson carbs and I have noticed a small flat on the throttle butterfly. It appears to be there to let a tiny amount of air to flow thru the venturi when the butterfly is closed.
I have seen this little flat both on the float bowl side and on others it was on the opposite side of the butterfly.
Have you ever seen this or might it be some form of mod?
Any insight will be appreciated.
I have made a jig to hold the top casting in my milling machine to flatten it by milling off a few thousandth of an inch, as they are almost always warped and I fear the usual method of flattening the underside of the top flange by using a hammer.
I can e-mail pictures if needed.
Thanks,
Tom in Arkansas
tom@k4viz.com

 

[Bill in SoCal]

I don't know much about rebuilding a Tillotson carburetor. Cut and past this information into a Google search mrtexascitrus/home/tilly-carburetors

You should get plenty of information on rebuilding a Tillotson. You can also use the search engine on this forum. Just enter Tillotson. Good luck, Bill