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).
Investigation into carburetter flooding caused by foreign matter originating from the flexible pipe.
| Identifier | ExFiles\Box 102\1\ scan0339 | |
| Date | 25th June 1935 | |
| -4- We next turned our attention to the complaint of flooding. The first carburetter that we actually saw flooding badly was the one fitted to Sg{Arthur F. Sidgreaves - MD}'s car, at Lillie Hall, and at first sight it gave one the impression of either some form of syphoning or a faulty float mechanism, but our investigations proved to us that neither of these conditions were the cause of the trouble, but that some form of foreign matter was getting between the needle valve and the needle valve seating, thereby not shutting off the petrol supply when the float was at the top of its travel. One experiment was to place foreign matter obtained from our standard plate filter containers (stuff which does not pass through the plate filter) into the flexible pipe and allow same to flow with the petrol into a perfectly clean carburetter. The result was copious flooding in a few minutes. The foreign matter that had lodged between the needle valve and its seat was carefully removed and photographed. Attached is a copy of the micro-examination report with photographs. This foreign matter does not under ordinary circumstances get past the plate filter, and we therefore concluded that a certain amount, sufficient to cause flooding, must come from the flexible pipe itself. A report by Hs{Lord Ernest Hives - Chair}/Dwg. will follow upon his experiments with flexible pipes. These conditions call for a filter at the point where the flexible pipe is attached to the carburetter, and a design to Lec. 4509 has been drawn out to give this. As soon as obtainable these filters will be fitted to Experimental cars, Sg{Arthur F. Sidgreaves - MD}'s car, and G's car, and are being fitted to production cars as soon as possible. Hs{Lord Ernest Hives - Chair}/C.H. Whyman. | ||