"BGM PRO carburetor revision kits contain high quality spare parts to restore an existing carburetor to factory condition.
The set contains not only the seals but also the very important float needle.
This ensures that the carburettor does not overflow and that the engine has a stable idling speed.
TIP: For a perfectly sealing surface, work up the float needle seat (usually made of brass) with a cotton swab (Q-tip) and some chrome polish. This is important in order to remove any residues that may occur frequently in carburettors that have stood longer.
The basic setting of the mixture screw is usually between 1½ and 2½ revolutions. To do this, gently turn the mixture screw to the stop and then turn it out again by the above value. The mixture screw determines how rich or lean the mixture is in the lower to middle range. An engine running too rich stutters (four-stroke) and does not reach the correct speed. An engine that is tuned too lean only reluctantly accepts the throttle and even tends to die when suddenly accelerating. If the main nozzle and the choke function are in order, the first step should be to overhaul the carburettor with a revision kit as offered here. After the basic setting, the scooter should have a stable idle speed and a good throttle response."