It's a troy-bilt trimmer with a ryobi 4-stroke engine. It calls for 30w, and holds a whoppin 3.4 ounces. I got a 1/2 qt of valvoline 10w40 motorcycle oil, some pennzoil 10w30 pzl turbo API SH, 1/2 qt of german castrol (green), an old qt of mobil1 10w30 API SH, and some valvoline vr1 10w30 that has a bunch a zinc in it. The oil doesent get hot in it like you might think. My lawn mower is a 2-stroke, and I have no other uses for these oils. Also, does anyone know if this engine is splash lubricated?