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.
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.
SAE 30 weight.
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.
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.
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.
Displacement and HP are only related to each other in a range because of engine variations. I agree but was curious how did you get the cc of a lawnmower? If it is a lawnmower the hp comes out with an educated guess of about 12 hp.
You do not state if it is a single or a twin (which it could be of either at that HP) so links to each below: