Originally Posted By: bubbatime
Briggs has always recommended a 30 weight for as long as I can remember. The fact that they recommend a synthetic 50 weight for hard use engines is quite interesting. This is what we call a "clue".
For years, since the 2004 hurricane season, I have recommended synthetic 50 weight in all generator applications down here. All Kawasaki engines a 40 weight, all commercial Briggs engines at least 15W40, and SAE 30 or synthetic 10W30 for home owner Briggs equipment.
Briggs must be tired of warrantying engines and has finally figured out what a lot of us already knew.
Why all Kawasaki engines get a 40 weight? Kawasaki recommends 30, 10w30, 10w40, 20w50 and 5w20(if used below 32 degrees). Basically you could use 30 to 50 weight on a Kawasaki. I have 5w30 full synthetic in my Kawasaki lawn mower that gets ran half hour at a time. Would you recommend to use something of a 40 weight?