I recently purchaced my first bat and motor (1986 9.9 Evinrude Yachtwin - model E10SELCDB). While looking online about the motor I came across one for sale (not sure what year but it was a 9.9 Evinrude Yachtwin), and it was being advertsed with a built-in altenator to charge a battery. I was wondering if this was a feature of all these models and if not how would I know if I had one? Also I need to make sure, is my fuel mix supposed to be 50:1? Thanks for any help supplied.