I have an old Perkins 30hp outboard which I have rebuilt after one of the poppet valve guides had broken off. I bought the engine as a non runner and the previous owner gave me a second-hand, replacement valve casting. The engine is now back together and is running, but is coughing back badly. In the Users Guide for the engine, it says that to tune the engine sucessfully, the throttle should be syncronised with the variable timing, but it does not say how to do this, does anyone have any ideas.
Any advice will be very gratefully received.
Bob