Yamaha generator oil

He is using it at negative 20 C. The 5W30 is fine. No need for a 40 weight oil at those temps.

I’d be worried about the cold pour point of the boat oil? Is it published?
I have that genset and its been fantastic - if a bit heavy.

I run something 0-10W-30 in the cold and 0w-40 when its hot out.
I have one as well, over 600 hours on it with only a battery replacement. It has always had RP HPS 5W30 in it other than the rotella 15-40 I used for the break in. Yes, its a tank
Amazing, all this "I would use this and that".

Manual claims 10-30W. Message ends there guys. 0 grade oils? Really? Unit calls for a 10 grade oil.
Which is a lighter oil (5W) and get past the rings. Less protection and more oil usage. Where's the benefit?
In the -20 temperature it will be used in, 0w-30 and 5w-30 will make the engine much easier to start than a 10w-30. Also, in that temperature air cooled engines will be loaded with very low oil temperatures long after being started. Slight shearing of the oil will be utterly harmless under those conditions. I've used 5w-30 in my Honda inverter generator during hot August weather since I didn't have 10w-30 at the time with no noticeable oil consumption.