One of my buddy piaggio fly4t4v 80 cc ,was shutting down all of a sudden on the road,he had tobstop,start it back and it would shut down again.

So he sent his fly to his city vespa garage and the guya there deleted the intake vacuum line from the pet cock,he is now complaining about a loss of power since then,but the fly does not shut down anymore.

My question is;since there is no vacuum from the carb to the intake,could that be the reason for that power loss?
Im wating picture of the gas tank to see if they also deleted the pet cock,which would definitively restraint gas flow if they left it there with no vac connected to it.