Filament gets stuck. Can't find the problem

Hello Everyone,

I have a Geeetech I3 printer. I am printing with PLA.
Since my hotend troath was broken, I replaced it with a new one.
I also cleaned the nozzle and the heater element.
After the replacement from the troath my filament gets stuck when I start printing.

When I startup the printer, without filament (because I have just cleaned the nozzle etc.) I select ''preheat PLA''
The printer will warm up to 210 degrees celcius, the temperature my filament dealer recommend me.
When the printer is at the right temperature, I can start putting in the filament by hand. Hold down the
gearwheel wich push the filament in the extruder. The filament starts coming out of the nozzle and seems ok.

Then I select the funcion to print from my SD card, where I have stored the 3d print gcode.
The printer is heating up the heated bed and will start printing. The problem is that there is no filament coming out of the nozzle
anymore. I can see the extruder gear trying to push the filament into the nozzle, but no succes...

When I pull out the filament it has a bit of a brown burn mark, and a strange shape.
Here are 2 pictures:




Who can help me out with this problem?

I am using a MK8 extruder, the filament is 1.75mm and I use a teflon tube to guide the filament trough the nozzle (exactly as
geeetech delivered the product)

No matter what your dealer said, you need to lower the temperature to probably 190 to 195 tops, those MK8 extruder/hotend assemblies dont have too much cooling capabilities, the melted filament is jamming on the cold side of the hotend. But the bigger issue you are facing is the teflon tubing, looks like is either too short or it is deformed at probably the side facing the nozzle. Take the nozzle out and look for melted plastic in the threads or black color at the end of the tube.

That second picture looks to me characteristic of filament being left behind in the hotend
when you pulled the white filament out.
Google "how to cold pull a nozzle". Works a charm with PLA and is the easiest way to
clean a nozzle.

Can you get the host software to feed filament when the hotend is away from the bed?