In recommended straight 40 weight all I could find is non synthetic Valvoline racing oil. Is this acceptable?
Got mine on Amz, just search for 40wt oil. Fun fact: I've also used it for some gunsmithing stuff i.e oiling my sight platform screws(was installing a Sight magnifier and it was a tad bit too tight)
If you want a synthetic 40w oil, Royal Purple makes one. Sorry I can't remember where I bought it.
The manual simply recommends 40 wt. motor oil, so any type should be OK.
JohnK