I don't know if it's for the pump or what. there is a cap on top of the engine that says 'oil' and it has a dip stick attatched to it.
That sounds like the engine oil then. No problem using automotive oils in that, straight 30W or a narrow multi-vis like 10W-30.
The oil for the pump is separate and you don't want to use automotive oil in that because of detergents and additives in engine oil. It's probably filled through a pipe plug or other hex fitting on the pump body itself, and might have a sight glass for oil level rather than a dipstick.
Sberry is correct; straight 30 weight, but go with the high detergent. Non-detergent was used in the old days but detergent oil is recommended for newer engines. multi grade oils can increase oil usage.