Synch between the film images and the sound will not match perfectly unless you use a pilot tone or similar system to synch the tape recorder and camera. Since you're probably shooting reversal film and ending up with a single copy of your work, it's worth it to invest fifty or a hundred dollars in a decent projector, and to keep your film cleaned and lubricated. Then run a piece of Super8 leader, or a piece of scrap film, through the projector, and carefully inspect it for scratches or wear. There is a very good chance that the film was never lubricated in processing. Everyone used to do this but now even Kodak doesn't bother.
Unlubricated film has a high and inconsistent friction level.
Lubricate it with candle wax or beeswax dissolved in film cleaner, methyl chloroform or Freon TF if you can find it. The general rule of thumb is a lump of wax about the size of a pea, dissolved in 8 oz. of solvent. Moisten a clean rag with it, and pull the film through slowly enough that it is dry before it takes up. Post to the group for suggestions. Exposure Index, also filmspeed.