Just visited my local Tractor Supply store. They have on the oil shelf, their Traveller brand NON Detergent SAE 30 in quarts for 3.49 and gallons for $13 and change. They also have SAE 30 single weight detergent flavor. SAE 30 is recommended for all operation above 32 degrees f. If you operate below 32 down to 10 degrees SAE 20 is the advised viscosity.