I have a Kenmore 21168 freezer(not frost free) which has developed a problem keeping cold. I can hear the compressor start, sounds ok, run and shuts off after 3-4 seconds. It will do this repeatedly and has been doing this for a few weeks now but has gotten worse. Now temps inside are around 32 degrees(f). I defrosted last week and thought things got better as temperatures got -8 degrees. Now, they are back to 32 and will not go lower due to the short cycling. I would appreciate any suggestions, I would repair as long as it is not the compressor. Thanks.

It's probably your overload, or start device. Nothing exciting.

But you did leave off most of the model #, it'll be on the inside of the cabinet, starting with 106 or 417 probably. That'll help ID the part #.