Can I use this oil?

I'm not a chemist, but years ago I had some instruction manuals that warned against using 10w40 over 10w30 - the explanation was that you got more additives and less actual lubrication. Made sense to me because at the time I was running straight 30w or 10w30 in my Class C because it wouldn't burn a quart every tankful like the 10w40 would. So I would guess that 10w40 will break down quicker.

in HOT weather, i prefer 10-40
i will use 5-30w in the winter

..and you are in northern Idaho.

From a lubrication stand point 10W40 should work fine. I tried doing the same with my Honda 2000. All was well until I tried running it in very cold weather. The Honda shut down via the Low Oil Level Sensor because the cold 10W40 was sticking to the inside walls of the engine hence Low Oil Level alarm. It would start, run for a few seconds, and then stop. I would wait 30 seconds, pull the starter rope, and a few seconds later, it would stop with the Oil Level lite showing. I am back to using 5W30.

LeRoy