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).
Petrol grades, fuel supply, and carburettor adjustments.
| Identifier | ExFiles\Box 178\1\ img069 | |
| Date | 26th November 1925 | |
| - 8 - EXPERIMENTAL REPORT. EXPL. No. REF. Hs{Lord Ernest Hives - Chair}/ACL/LG261125. grade of petrol or a cold hot-spot - could give rise to symptoms which might be mistaken for faulty metering of the carburetter and although correct metering tends to promote good distribution it will not correct an induction system which is at fault. To guard against this trouble - as well as others likely to occur through the use of a poor grade petrol - only good grades should be employed. With regard to the use of special fuels, if desired a 50/50 mixture of good petrol and benzol can be used and should not necessitate any alteration to the mechanical adjustment of the carburetter. The petrol supply should be adequate for the demand of the engine i.e. not less than 85 pts/hr. should pass through the two plug holes beneath the high and low speed jets with a 15" petrol head. If this flow is not obtained the collar on float chamber needle valve should be suspected because if this has been raised from its correct position on the shoulder of the needle valve - in order to alter the petrol level - the lift of the needle valve will be restricted when the float is at its lowest position and result in a reduction of the maximum petrol flow through the carburetter. As air and fuel temperature have considerable influence upon carburation, it cannot be too strongly emphasised that adjustment should not be made until the engine has attained its (contd). | ||