chinese portable generator gives low voltage

Most pips buy the chinese made portable generating sets because they are cheap. but they can also come with their own problems. This might be the reason why most of these small generating sets come with spanners and screws in order to enable self service. After a period of use, if your portable generating set starts giving a low voltage, the most likely place you should look at is the piston where your spark plug is mounted.
       First of all remove the spark plug, clean it thoroughly, then loosen the block in which the spark plug was inserted, you should be seeing the piston head after doing this. Also, you will notice that the piston head is covered in black soot. also check the head of the block you just removed, you might find soot also. clean and scrape both as much as you can.
       You can now couple the block. Don't forget to fix the spark plug. Try not to forget anything you removed. Start your portable generator afterwards. The voltage should be normal and stable now. If the voltage is still low, you might want to increase it by using a screw driver to turn the screw directly under the fuel tank in a clockwise direction. If after some time, the voltage drops again, then that means the generating set's vibration is loosening the screw...you might want to secure the screw somehow, or take the generating set to a technician for repairs.

thanks pips.