If your watch is running fast or slow you will likely need to adjust the timing of your watch.

I would first recommend demagnetizing your watch as this can often be a major cause of time gains or losses.
To adjust the time of a Timex watch requires a little trial and error. Inside the watch accessible without dismantling the watch and located behind the balance wheel is a small lever. This can be moved up or down using a pin. Be sure to not touch the balance wheel. 

Moving the arm upwards makes the watch faster, downwards slower (i think). 

There are no notches so its all done via small ad-hoc movements. I suggest moving the arm and testing the time over an hour or two.

Once its keeping time over these short periods then try timing the piece over a day and make further micro adjustments.

I don’t have one but would suggest getting a timegraphing machine which gives you detailed on the spot analysis and will allow you to fully calibrate a watch in under an hour.