Why is my engine bogging?

So I recently got my moped started and running but it wouldn't move under it's own power so I decided to add a metal washer or shim in the clutch pack because it's hard to find new parts for this moped, and after that it started to move under its own but the kickstart was tight and when it did start, it would move but not very fast, like 8 mph, and it would bog at some points and even die and I even have the hold the starter lever to make sure the clutch engages. Can anyone tell me how to resolve this?