Dont know if this will help...Im not a mechanic either but ride a LX150.
Idle Adjustment: (for the LX125 or LX150)
1. Rest the scooter on its center stand and lift the saddle
2. Remove helmet compartment
3. To adjust the idle speed, start the engine, then loose or tighten the idle screw until you reach the idle speed taking care the engine does not make the rear wheel move
* Idle speed must be adjusted when the engine is hot. Before this operation, make sure that the throttle grip has the recommended backlash. If backlash in the throttle control transmission needs adjusting...take the scooter to a Piaggio Dealer/Service Center or your scooter mechanic.

Good luck!