Butterfly disc seating

[Mr Spigot]

I have just been rebuilding an SU HIF6 carburettor and fitted a new butterfly disc. Having fitted it and tightened the screws, I notice that the disc does not seat fully against the carb body (see photo) as there is a small amount of light showing through the gap. Is this acceptable? I know that the HIF44 disc is slightly smaller, so made sure I got an HIF6 one.

[Mr Spigot]

Upon further investigation, I realised I had not slackened off the choke and idle adjusting screws, so it would not close fully. Having done so, the gap is now almost imperceptible. Silly me! Over 40 years playing with Morris Minors and I still have lots to learn!

[Bill_qaz]

The more hindsight you have the wiser you become

[philthehill]

When fitting the butterfly to the spindle leave the butterfly loose in the throttle spindle and with the butterfly spit screws fitted but not fully tightened. Slacken right off the throttle idle screw. Close the throttle/butterfly fully so that closing the butterfly will centralise the butterfly in the throttle spindle and carb body. The butterfly should be fitted so that the bevelled edge of the butterfly should come up against the throttle body. Fully tighten the butterfly split screws with the butterfly pressed against the carb body. When the screws are tight and the butterfly centralised open the split ends of the screws so that they cannot come away from the throttle spindle.