NO,
99% of all old electrically cooled soda machines are outdoor rated and do not need a GFI, they do need a grounded outlet, as I said before, you never put any motorized machine on a GFI, that includes washers, dryers, refrigerators, drill presses........etc. why? because if you do, the electric motors will pop it every time, why? because of the amount of current needed to start the bloody things upon startup will cause a huge surge of input current, which then causes a huge magnetic field to build to start the motor spinning, this magnetic field then creates a counter-current in the metal of the case of the motor & surrounding metal of the chassis, which naturally seeks ground, so what does the GFI do when it sees this surge of current in the ground wire? it trips just like it's supposed to do.
NO NO NO GFI's on soda machine circuts... (hint hint)