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).
Schematic diagram of a Zenith slow running system.
| Identifier | ExFiles\Box 13\3\ 03-page321 | |
| Date | 25th May 1931 | |
| ZENITH SLOW RUNNING SCH THROTTLE EDGE TOP DISCHARGE HOLE FOUR AIR HOLES DRILLED DOWN TO INTAKE SMALL DISCHARGE HOLE ABOVE THROTTLE DISCHARGE HOLE WITH MOVEABLE RESTRICTIONS UNCOVERED WHEN THROTTLE IS SLIGHTLY OPENED. AIR BLEED ADJ. SCREW IDLING JET JET TUBE SSV WOLUM 25 MAY 31 WEP | ||