What can that be? Baotian Qt 12

once again a small problem… … with the starter now where it is colder the starter turns very slowly (almost from listening like a short circuit) so he manages to turn the motor just like that also the starter sounds to start again and again at the attempt (so the starter runs then really fast but the motor is not driven anymore) only with a new attempt he attacks again in the engine (I understand the technology) , but can explain it just badly ) so the battery ( 4 ah ) is new , the starter motor turns “normal” when he does not engage and the (shit how is now this part again ) “taker ???” is smooth (had I expanded ) what could be the problem ?