Lawn mower oil, can you use 10W40 motor oil in it? Will that damage the mower?

This is a 6 hp lawn mower, by Toro.Lawn mower oil, can you use 10W40 motor oil in it? Will that damage the mower?
It shouldn't hurt it, the warmer it gets the lighter the oil becomes.really something like a straight 30 or 40 weight would be better.Lawn mower oil, can you use 10W40 motor oil in it? Will that damage the mower?
dunno, but last time i changed oil in a lawn mower it blew up 45 minutes later, actually it wheezed and coughed. ill never do it again for a splash system.last push mower i had sounded like it had a blacksmith inside it fouled the plug once a month and ran for 12 yrs starting on the first pull everytime and i just wanted to shoot it.a guy was taking 3 to the dump. i fixed 2 and 1 for parts, sold 1 kept 1.heck it didnt even use oil till i got it so hot it smoked for 2 hrs and caught fire etc, lol i got a teen boy he was suppossed to cut the grass, skipped the thick spot about a month, ever cut bermuda at a foot tall or so?
you can use it. I got a old snapper that is 22 years oold and I just put in 20w 50 to quiet it down. Runs great.
Sure you can use it or any type of motor oil. I do, and don't have a mower less than 10yrs old (I usually ditch them after 20 years working or not)