If you're gonna use it late into the fall Bill... 10W30.. and any good quality engine oil will suffice. That is all the marina uses for every small engine in the yard. Gear case.. I use the Merc High Performance in mine, mainly because I have to put that in the Verado lower end and don't want two filler pumps going, but give thought to that kicker working hard if you happen to use it to troll for skis...Make sure you buy a high quality 90W lower unit oil.