I had my boat into the service guy yesterday with some issues I have been having. My sparkplugs are fowling out after approx 60 gallons of gas. He asked what oil I was running, told him XD50 and he told me to use XD100. He said that he uses XD100 in all of his engines that he services. I didn't think I should, but is it OK if I do????? My motor is a 2004 225HO DI (NOT THE ETEC).

Thank you, Brad