That air leak won't cause a rattle (unless it causes pinging from being lean) , it will cause running issues like high idle/hanging idle , hard cold starting ,steady speed surging/feeling like running out of gas , popping on decel ,lazy power in higher rpms, ect... due to a lean mixture . Any of these dual carbs /dual intake boots setups it's always recommended to replace both at the same time if one is found to be bad , most times the other is just about as bad or getting close and will be shot shortly , might as well fix once and then done.

It will definitely run better once fixed.


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