Between 25 to 35 oz. depending on the model some may take more. Start by adding 3/4 (aprox 25oz) of a bottle of small engine oil NOT 2 STROKE OIL!! Then check the oil level on the dipstick. Add more as needed.
1 and 1/2 quarts. 1/2 quart. Over filling will sometimes cause the engine to lockup. Also check to make sure enough oil is in the engine. It'll run without oil for awhile, but ends up causing your engine to freeze up.