206 injector problem

Good evening everyone. I have a 2000 model 206 Roland Garros 1.6 gasoline+LPG. The fuel injectors in my car have milliseconds of around 9-10, while the gas injectors have milliseconds of around 13-14. Also, the engine is getting a rich mixture. Does this have anything to do with it? How can I adjust the milliseconds of the gasoline? I couldn't find a place that does this in Ankara. Any help would be appreciated.