How can i fix a malfunctioning moped odometer?

I recently bought a 1988 General TE Moped. It was in brand new conditions. Literally. it was very clean and said that it had only 43 original miles. i have been riding it to break it in and recently made it past 100 miles. However the odometer jumped from 100 miles to 300 and then 1000 etc. i am sure it must not have more than 130 miles but the odometer now reads that it has over 3600 miles. my guess is that since it was not used much, the inner workings of the odometer got stuck somehow. the speedometer works fine. i guess my real question is whether the odometer can be fixed and returned to more or less the correct mileage. I am interested in this for oil changes and the break in period more than anything.