Time Runner (no wikipedia entry) is a 1993 film starring Mark Hamill. It does not appear to be available on DVD, and the VHS is, of course, out of print.
Youtube has parts of this online. This is not the entire film, but it does a coherent job of presenting the part of the movie that features Mark Hamill and takes place in The Past (our 1990's present). Half of the movie, though, is completely omitted here. It does a violence to the film, so that it's hard to tell if the film is really that bad or if it's just been butchered. Part 1:
part 2, part 3, part 4, part 5, part 6, part 7, part 8
EW gave it a C-. io9 calls this "the low point of his [Hamill's] post-Star Wars career." This site gives an ongoing description of the complete movie as it's being watched.