I get very small pause at the end of animation wich i cant eliminate. My poor animation knowledge wont let it go away. Maybe some skilled animators can help me out. here is fbx file.
It looks like your last frame is the same as your first that’s why you get a pause. Ideally you would fix this in the animation program by copying the second to the last frame and pasting it over the last frame so that the frame that plays before repeating the first is an instance just before and not the same instance back to back.
I played around a little with your file and found that if I import it using Animation Length: Set Range: 1 - 26 it and then setting the Rate Scale in the animation itself to .8, it had a fairly smooth playback although the character seems to walk with a bit of a limp.
yes i fixed animation a bit. still learning 
also there was a frame beyond indicated that could be issue too. but it looks pretty good now. still need to learn about human movement a bit character look bit like robot
Simple fix = copy the first frame to the last, keyframe the next to last, delete the last.