I know that the mechanical Timexes are not designed like other watches, yet the theory still applies to Timexes too; however the methods to apply it may vary from traditional watches.
If the watch is cleaned, examined, oiled and it still runs fast, then weight will have to be added. I cringe at saying this but to slow it down, add weight around the balance with timing washers epoxied into placed 180 degrees apart. Maybe epoxy placed by itself would work. The weight will slow it down; just make sure that the epoxy does not rub any part of the movement, and if weight has to be added in more than one location on the balance rim, place the weight (epoxy) on each end of the rim to balance out the distribution of weight. The epoxy will slow the timing down, yet throw the watch out of poise. There is a method of dynamically poising the wheel, but it requires the use of a timing machine. If you have old movements that have balance wheels with screws on them, check under the screws for timing washers.