Generator oil - ideal all-weather fill?

[Jetronic]

So I was down at my mom's place this past weekend cleaning some stuff out of the shed that my dad had left in there before he passed away, and I found a generator that doesn't seem to have had much use. It's a DuroStar DS4000s, and the manual says that it likes 5w-30 below about 30 degrees, 10w-30 between about -5 and about 90, and straight 30 above about 55. Based on what I know, it's kind of an idiosyncratic set of recommendations- see the picture. What I'm trying to figure out is what the ideal oil for it might be for year-round standby use; here in Dallas we routinely have winter temps in the 20s, and summer temps around 105.

I'm thinking maybe something like a synthetic 10w-30 of some sort, or even the old jug of SN rated Mobil 1 0w-30 that I have out there might work adequately in the event of a power failure. What I don't want to do is seasonal oil changes for a standby generator. Any opinions?

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They want high hths when it's warm, hence the straight 30. The 5w-30 is likely to shear in use and end up comparable to a 20.

5w-40 or 0w-40 would be good all year round. If the 0w-30 is an ilsac I wouldn't use it unless in winter.

 

[kschachn]

The only "advantage" to a specific natural gas engine oil is low ash which can be obtained in many other oils.

 

[mark pruett]

They want high hths when it's warm, hence the straight 30. The 5w-30 is likely to shear in use and end up comparable to a 20.

5w-40 or 0w-40 would be good all year round. If the 0w-30 is an ilsac I wouldn't use it unless in winter.

The only "advantage" to a specific natural gas engine oil is low ash which can be obtained in many other oils.

I figure this Valvoline Premium Blue stuff is the best all-around option; high HTHS, manual-specified viscosity, HDEO additive pack, and NG compatibility, for what that's worth.