J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment 1981 J30 Engine

I am about to buy an 81 J30 and upon surveying the boat today we found it had a Yanmar 2GM engine instead of the 2QM15. Does anyone know anything about this change and know anything about the differences in the engines. Also is there a masthead light on the J30? We could not see any sign of one with binoculars since the mast is up. Thanks, Paul