From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Letter from The S.U. Carburetter Co. Ltd. detailing carburetter disc clearance and spring selection.
| Identifier | ExFiles\Box 121\4\ scan0214 | |
| Date | 6th October 1938 | |
| THE S.U. CARBURETTER CO. LTD. RLK/ER CONTINUATION No. 2 Messrs. Rolls-Royce Ltd. 6th October 1938. the number which represents the clearance on the diameter between the disc and the cylinder in which it moves, thus '55' stamped on the disc represents a difference in diameter of .055". In determining the correct spring, we usually make sure that the disc cannot be drawn down on the starter, even with a warm engine. To carry out this test it is, of course, necessary to disconnect the coil so that the engine will not start whilst you are spinning it on the starter. If the disc can get drawn down the mixture may not be rich enough to provide a start. If the spring is too strong, there is a greater likelihood of bad starting with a partially warm engine, and also a richer mixture than is necessary is being used under cruising conditions. on the road with the starting carburetter in action. Yours faithfully, For THE S.U. CARBURETTER CO. LTD. Leslie Kent | ||