The user's guide to my 130 series B&S engine (garden cultivator) says: 10W-40 can be used if 10W-30 is not available at your location. So, if you fit to the 10W-30 oil temperature interval then 10W-40 can be used.
On the other hand lawnmower is usually used at spring-summer temperatures so why not to use SAE30 oil?
Lawnmower. It's a Briggs & Stratton engine.
what grade of oil on this engine
Briggs & Stratton
Briggs has a rudimentary wiring diagram for the operation of an electric start engine. see the link below.
The correct gap for the spark plug of a Briggs and Stratton 6.75 Lawnmower engine 0.030. Most new plugs come with that gap, but it is best to check to make sure.
SAE 30 weight.
why does my 4.75 BRIGGS & STRATTON lawnmower engine idles high and low when cutting my grass
It is 0.030" for an L-head engine.
Briggs and Stratton is a select brand of lawn mower. When oiling one's Briggs and Stratton lawn mower engine, it is best to use a high quality oil. One can find such an oil at their local home improvement store, such as Home Depot.
My 6.75hp Briggs calls for 30wt, so I would make a reasonable assumption that the 6.5hp calls for the same.
It is probably a Briggs & Stratton engine. You will need to supply the model number from the engine to get a correct gap.
A 159 cc Briggs and Stratton lawnmower engine typically produces around 5 to 6 horsepower. The exact horsepower can vary depending on the specific engine model and its design. In general, smaller engines like this one are designed for residential use, providing sufficient power for typical lawn care tasks.