Like I said before.... be sure to change the oil @ the recommended intervals...... If it were me.... I'd use synthetic oil but check with the manuf.
The paperwork shows three different recommendations for oil... depending on the air temperature. Two out of three is recommends "regular" oil... the upper operating temp. shows synthetic. I am tempted to stick with the recommend weights and use synthetic regardless of the air temp.... which after-all may change one day to the next. I believe the first oil change is at 50hrs on this unit, but I need to double check that and be sure.