In simple words the engine is what makes the scooter go without your effort!!! (leg pushing).

Choose the most suitable engine to do such a job and never forget it must be as cheap as possible (never forget the money factor - if this is not important, buy a motor scooter ready to run).

If you read the -How does it work- chapter you now understand that there is a -direct- connection between the engine and the rear wheel, that means that when the Scooter stops the engine must be disconnected from the rear wheel. To make it clearer it means that after every stop you will have to disconnect your engine from the rear wheel and all that will have to be done while the motorized Scooter is still running.

Don't worry.

What we need is an engine with a clutch, the clutch is responsible for disconnecting the engine movement from the rear wheel. when you whant to drive the clutch is engaging between the engine and the rear wheel. when you whant to stop the Motor Scooter the clutch will disengage the rear wheel from the motor without the shutdown of the engine.

But where can we find that kind of an engine without paying!!!

There is a very cheap engine that can be use for this job - a Grass Trimmer engine. That can be bought in grudge sale for a real burgeon.