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).
Carburetter petrol flow and float weight.
| Identifier | ExFiles\Box 66a\1\ scan0066 | |
| Date | 29th September 1925 | |
| R.R. 493A (50 H) (D.D. 31. 12-6-25) J.H.B. EXPERIMENTAL REPORT. Expl. No. 48080 REF: Hs{Lord Ernest Hives - Chair}/ACL1/LG29.9.25. To BY.{R.W. Bailey - Chief Engineer} from Hs.{Lord Ernest Hives - Chair} c. to Wor.{Arthur Wormald - General Works Manager} c. to Sft.{Mr Swift} c. to Mr. E.A.C. CARBURETTER. PETROL FLOW AND FLOAT WEIGHT. It has been found that lately some carburetters have been fitted with floats which are too heavy and in order to get the level down to the specified limits, the collar on the needle valve has been raised. The raising of this collar from its normal position restricted the lift of the needle valve when the float is at its lowest position and consequently reduces the maximum flow of petrol through the carburetter. This collar on the needle valve should not be moved. Its correct position is right up to the collar formed by the larger diameter on the needle. It should be quite unnecessary to make adjustment here if the float is of the correct weight and dimensions. The weight of the float should be 2.65 ± .15 ozs. and should give a petrol level of 1.3 + .10 - .10 from the top of the float chamber with fuel of a specific gravity .758. To check the rate of flow of petrol through the jet plugs a 15" head should be used. The flow must not be less than 85 pts/hr. when passing through the two plug holes beneath the high and low speed jets. The limits for the weight of float given here supercedes that previously given in the report on Setting up and Fitting Carburetter. Hs{Lord Ernest Hives - Chair}/ACL. | ||