Welcome to OCC
To best determine approximate value, first you need to tell us the model number like 109 149 etc.
Pictures are must, just like selling anything.
As far as "motor rebuilt" some consider that a new paint job and a spark plug possibly a carb cleaning.
A "rebuilt engine" has been bored oversize with new piston and rings, valves ground and the crankshaft turned undersize with new connecting rod as well as other wearable parts.
