Use only regular unleaded ethanol-free.
I use multi-weight synthetics in my small engines. 10W-30. The “Tech” brand from Walmart.
Use it in my cars too. Significantly less than the name brands and every bit the same. These oils are refined and packed in the same facilities. Just change the labe on the container.
Straight regular gasoline doesn’t exist in most Midwest markets.
Premium is the alternative...