Citystar 125 does not jump after a few days

Moin dear two wheel specialists, My father’s 125 city star has been having problems for months. He is drinking overnight and no longer jumps. He has now received the following new parts: Ignition: – Spark plug – Ignition cable – Ignition coil Other: – Starter – Injection nozzle The problem is expressed as follows, you try to start the scooter off and to jump it immediately then it runs without problems, you can also turn off the scooter several km at a time, ice cream, shopping etc. d Then you get home and put the scooter under a roof. If the scooter is now standing for a few days, it does not start at 90% and is drunk, if you then expand the spark plug and put it dry or install a spare ignition plug it starts up and runs again as described above. I have already read in another thread about it that some scooters have an anti-fluod function with injection (give full throttle and press 5 sec starter) but this he has nic If you give full throttle and ignite it completely injects. I am getting really helpless, I had the assumption that the injection nozzle drips after and therefore a new verb. Unfortunately, the error still exists. Maybe you still have an idea. LG Noisefreak