what type of oil

I know this isnt a car question but it has to do with engines. I'm putting back together a go kart engine and I dont know what type of oil it uses. My friend who sold it to me doesnt know cause someoen gave it to him. I was wondering if using lawn mower engine oil (10w30) would harm the engine in anyway. thanks - Andrew

well you could always get #'ers or a name off of the engine and google search it. 5w30/10w30 or any similar weight oil should be fine I would think.