Small Engines (Lawn Mowers, etc.): old B&D grass trimmer, grass trimmer, nylon 1

Question
Which is the correct string for an old Black & Decker grass trimmer (nro. 8209-22 Type 3 2.4A, 220 V 50-60 Hz, 10500 rpm)?.
I have not used it for years. When trying to use it now, I find that the machine "looses" 5 meters of string in 10 seconds. Apparently the string is pulled out and cut continuosly.
I think that the nylon 1.5 milimeters diameter string I am using is not adequate for the machine, but I can not find the owner manual.
Thanks a lot for your time.
Rene

Answer
Have you tried .065 line.  This line is smaller than gas powered trimmer line.

Make sure the string is wound in the correct direction.  If it is wound incorrectly all the line will come out...based on previous experience.

Is there an arrow on the line spool to show the correct direction?
Eric