I doubt that you will find a manual or any repair info on this particular machine. It is similar to a lot of other badged Japanese machines. Timing is a tricky thing to do yourself too, if it is indeed off. Most machines are not out of time. Especially one that robust. If you are set on doing it yourself, you should learn as much about timing as you can on a machine similar to yours. Most are similar but if you learn a lot about similar machines they should apply to your machine too. What you are looking for is the hook to pass the needle JUST as the needle starts to retract upwards. I hope this helps.
~G~