I picked up a new snowblower this year. After my 5 hour break in. I plan on dropping the oil and putting in synthetic 5w 30. My dealer told me I should stay away from standard Automotive oils and use a good four cycle synthetic oil such as Briggs & Stratton, Amsoil or a few of the others that are intended for small engines. Is their suggestion a valid one? They said something about today's oil being intended for vehicles that are liquid cooled that have catalytic converters.