Rear tires are labed as same size but are not- is this harmful

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Newbie here- just got a '97 Ezgo TXT 36 volt- leans to driver's side- when searching for reason for lean- I found that rear tires are marked as same size but one is
larger than other- Cart was leaning to drivers side, the smaller tire side - so I swapped tire sides- cart now sets level- which it really should not. Would be ok to run with un-even tires?
I was not able to spot any reason for lean- where should I look? I need to get a service manual also- suggestion- on-line anywhere? I am reasonable mechanical- I build outboards.