The First World War

During the First World War, the S.U Company Ltd. became engaged on munitions contracts, which included making carburetters for Aero engines, with a staff of about 250. Normal production resumed after the War but the company had few customers and it showed a loss for 1919 and 1920. Although the S.U 'Sloper' had the advantage of automatically adjusting the flow of petrol to the engine, it was expensive and it had no proper means of providing a rich mixture for cold starting, other than 'flooding the float chamber'. This deficiency was tackled by Wolseley Motors Ltd, who added another jet and a physically operated needle. Wolseleys patented their modification (no. 119187) in 1918, for which they received royalties from S.U.