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).
Conditions under which the 35-EX Phantom III engine is liable to stall.
| Identifier | ExFiles\Box 92\3\ scan0310 | |
| Date | 8th June 1937 | |
| 300a To Rm.{William Robotham - Chief Engineer} Typed 8.6.37 35-EX. PHANTOM III. Stalling of Engine. The engine is liable to stall under the following conditions:- (1) When starting hot, immediately after firing. Can be cured by opening hand throttle or by judicious use of accelerator pedal. (2) After burst of throttle when running light. This is due to the petrol delivered by the accelerator pump remaining in the induction system as a result of suddenly closing the throttle, and causing temporary richness. The fault will not occur if the pump is thrown out of action, or if there is a pause between opening up and shutting off, as this allows the petrol delivered by the pump to be used up. (3) If a high load is applied with engine speed below 500 r.p.m and the throttle opened suddenly, as when starting from rest in second gear with too little engine. This can be overcome by opening the hand throttle, by more gentle opening of the accelerator or by letting the clutch slip. It is very much less pronounced in reverse or bottom gear. All three faults indicate that the engine is particularly sensitive to changes of mixture strength below 500 r.p.m. and that the carburetter will deliver an excess of petrol for light running and low revs. if the accelerator pedal is depressed too hard under these conditions, owing to the action of the accelerator pump. The troubles do not occur with the hand throttle opened to give 10 m.p.h. minimum on top gear. This is also the only use we have found for this control. With regular driving of the car this peculiarity is allowed for without much trouble, and we understand that no customers complaints have been returned at Cricklewood on this account. Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux} | ||