Is this carb piece necessary??

[gsdog2]

I exchanged the stock carb of my 5/72 40 for a non-usa version which is vac advance dizzy compatable. I noticed my old carb had this spring tensioned 'lever' holding a 'weight' until the secondary is activated, then this 'lever' flips up releasing the 'weight'. The non-usa version has all the same stuff except for the 'lever', but there is a mounting hole for it......do I need this 'lever'? I could just switch it over. What does the 'weight' do anyways?? Thanks

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