Not sure which forum to post this, but I need to change the oil in an air cooled 2 cylinder gas engine Onan generator. The manual calls for 15W40 but all I see for that weight mentions diesel. Is that ok for this engine?
Super Tech 15w40 will fit the bill fine.
I have ran many hours using delavc/ST 15w40.
I have use of/cf2 in sae 30/40, pceo sae30/40/50, 20w50 also with good results for what it matters.
Any oil will treat you well as long as you do regular oil changes and keep it full.