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).
Engine performance issues related to fuel mixture, ignition, and carburettor settings.
| Identifier | ExFiles\Box 32\1\ Scan041 | |
| Date | 16th February 1915 guessed | |
| -2- - Contd. by careful driving in the very narrow roads about here, and the failing light. It was also found that the consumption had gone up tremendously, because it seemed necessary to run the car with the mixture always over to strong, to get a sufficiently rich mixture in the cylinders which are naturally weak - Nos. 1 & 6 This occurred on one Saturday evening journey. On the Sunday Mr, Olley and I removed all the ignition plugs, which we found to be very sooty and those of Nos. 3&4, having failed entirely on the battery ignition. With the engine cleaned up in this way we drained out this mixed petrol and Benzolite and substituted two gallons of highly volatile spirit, The engine then started up most beautifully from cold and ran well while still cold with the carburetter adjustment in the normal position. With this light spirit the engine would run and aarburet correctly, down to the very lowest speed possible. It therefore shows that when demonstrating an engine that it is highly desirable to use the lightest spirit one can procure . It was also noticed while using this light spirit that the carburetter control could be pushed over completely to the weak side without the engine missing fire, in fact, it seemed to fire very evenly until the combustion was so slow that with the ignition well advanced it popped back, generally into the carburetter showing that the combustion, although the speed was low, was going on during the whole of the power stroke and exhaust stroke. From this experience it would appear that the Contd. | ||