Yes.
From Sta-bils website:
Q: Can I use STA-BIL Fuel Stabilizer in fuel for both 2-cycle (gas and oil mixture) and 4-cycle engines? What about the number of engine cylinders (1, 2, 4, 6 or 8 cylinders)?
A: Yes, STA-BIL Fuel Stabilizer works equally well in fuel for both 2-cycle (gas and oil mixture) and 4-cycle engines. STA-BIL can be used in engines with any number of cylinders (e.g. 1, 2, 4, 6 or 8 cylinders).