Here is my first print with support layers (I already removed them). Too be honest - I counting on better. So now I see the printer needs some tuning, but I don’t know what exactly 
. I hope you help me to figure out the existing problems!
Well, at first glance, it looks like temperature and flow rate need to be better calibrated. Have you done a solid calibration cube? It’s the best way to get your flow rate dialled in. Also, if you are using pla, you should think about a cooling fan. What printer do you have?
I agree with @Tim_Rastall , the solid infill in the base shows under extrusion. The legs may be improper priming after retract?
Absolutely something is wrong with temperature/ flow rate. Your temp is a bit high imho, that is the reason for the ooz.
@Camerin_hahn i am printing with ABS at 240C. Should i lower the temp? 220C?
hmm. i don’t know if i would lower it that much. I don’t have much experience with ABS, but i may lower it like 5 degrees and try some simple shape, (ie 2 short vertical rods) if you get oozing, then i would lower it some more or play with the retraction.
@Camerin_hahn ok, i am done with experiments for today (its a 00:37 now). I will try tomorrow, thanks!
There is a fine line between too hot, and too cold, too hot will ooze, too cold could cause jamming issues in your extruder/hot end. I like to error on the side of slightly too cold. But that can cause layer adhesion issues and maybe some jamming, but it makes for prettier prints (at-least in pla)
I’d try turning off retraction while you are calibrating your extruder temperature and gear ratio. Make sure to measure your filament diameter. I’d print a solid calibration cube