I have a Troy Bilt TB4 blower that has a 3 oz oil capacity. The manual states oil changes at 40 hrs which seems super long to me given the small amount of oil, especially using it in a hot climate. I've been doing short OCI's at about 10 hours in an effort to get some internal cleaning done (the first oil change WAY overdue and the oil came out black as coal and very thick) but eventually I'll go back to a "normal" OCI but I doubt it'll be anywhere near 40 hrs, that just seems to be asking a lot of 3 oz of oil. FWIW I run whatever oil I have spare, typically a 5w30 PU or 15w40 Rotella. And yes I realize for the price of 3 oz of oil and 5 minutes of time there's no reason to feel like I have to stretch the interval out. I'm more curious than anything with these low capacity blowers and such, what can you really expect?