Why do you think you need a sync and link? What are the symptoms?
Before you try link and sync, make sure your idle mixture is tuned in.
Unless you (or someone else) changed an adjustment, timing and sync are probably about where they should be. I often have people come who messed with it, and could never get it right again.
It usually, turns out they rebuilt the carb, but didn't clean it out properly, or didn't get the idle mix right or something else fuel-related. So they started adjusting linkage.
Tell us the symptoms in detail before adjusting the settings.
UNLESS you just want to justify to your wife that this "old" engine needs to be replaced with a new 4-stroke. 
In that case, I'll pay for shipping to take that old motor off your hands, as a favor, of course.
