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).
Carburation issues, specifically loading up at low speeds and fuel level problems in the floatchamber.
| Identifier | ExFiles\Box 93\2\ scan0176 | |
| Date | 1st December 1936 | |
| To Rm.{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/GR.{George Ratcliffe} 308 1.12.36. PH.III. CARBURATION The worst feature is the loading up at low speeds (15 M.P.H.) full throttle. The following explanation will account for and almost cure the trouble from the carburetter itself. The petrol pumps do not maintain a reasonable level of fuel in the floatchamber at high speeds full throttle. The mixture iscorrected at high speeds by the fitting of a bye-pass jet .060" as used on the test bed. This jet is too large for low speed full throttle i.e. when the level is normal, especially on steep gradients. A much smaller bye-pass (.055") can be used to advantage when a more correct level is maintained at high speeds full throttle. Tests are to be carried out to reduce restriction still further at the needle and seating of the carburetter floatchamber, as no improvement in fuel delivery can be expected from these pumps. Rm{William Robotham - Chief Engineer}/GR.{George Ratcliffe} | ||