Best bet would be to look in your manual and see what the recommended engine oil is. 5W30 would probably be on the thin side unless your running in the dead of winter (below 30°F). I think most small engines still prefer 10W30. I've been running straight 30 weight in my lawnmowers for several years now. (They seem to burn a little less of it on hot days compared to 10W30.) I do however run 10W30 in the Deere's CV15 Kohler to keep the hydraulic valve lifters quiet and happy.