Most lawnmowers take half a litre of oil to refill. SAE 30 oil is the correct replacement as it’s designed specifically to run at hot temperatures and last longer.
You can find just over half a litre of Briggs and Stratton SAE 30 oil here Briggs & Stratton 100005E 4-stroke lawn mower engine oil SAE30, 0.6 l
This oil will be suitable for all small to medium sized engines.
You will also require a small funnel for replenishing the oil you can find one here Silverline 282421 Funnel Set – 4 Pieces (50, 75, 100 and 120 mm)
Please note all parts listed are personally picked and I have gone to the trouble of only selecting genuine parts where possible.
Leave me a comment on my Youtube channel if you can’t find a part. Just post your question in the comments section of any video and I will get back to you.
You can find my channel here https://www.youtube.com/c/MowerMan