How old is this lawnmower? Yard machines, Briggs and Stratton engine YBSXS.1581VA is what it says on the engine sticker, it's American, but was brought to the UK a long time ago :
Honda 464 Pan European Gxv120 petrol lawn Mower Engine Gwo | eBay
Riding Lawn Mowers for sale in Warwick, Rhode Island | Facebook Marketplace | Facebook