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).
Instruction sheet for adjusting a Winfield Model-SR updraft carburetor.
| Identifier | ExFiles\Box 146\3\ scan0251 | |
| Date | 17th December 1936 guessed | |
| IMPORTANT — This is a UPDRAFT CARBURETOR Instruction Sheet [Image Section with four diagrams of a Winfield Model-SR carburetor] Diagram Labels (common to all four): MANIFOLD THROTTLE STOP ADJUSTMENT THROTTLE ROD CHOKE CONTROL WINFIELD MODEL-SR GAS LINE CONNECTION Individual Diagram Arrows and Captions: 1. PUMP ADJUSTMENT THIS ARROW POINTS TO THE PUMP ADJUSTMENT 2. IDLING ADJUSTMENT THIS ARROW POINTS TO THE IDLING ADJUSTMENT 3. INTERMEDIATE ADJUSTMENT THIS ARROW POINTS TO THE INTERMEDIATE ADJUSTMENT 4. HIGH SPEED ADJUSTMENT THIS ARROW POINTS TO THE HIGH SPEED ADJUSTMENT All adjustments on the Model “SR” Winfield carburetor are marked for identification. The “idle” and “pump” adjustments are marked on top of the serrated heads. The intermediate and high speed adjustments are made richer by unscrewing or turning to the left (anti-clock-wise). The pump adjustment is made richer by turning to the right; the richest adjustment being obtained when it is screwed completely against its seat. NOW YOU ARE READY FOR THE TRIAL ADJUSTMENTS—First turn all adjustments (clockwise) against their seats but don’t use too much force as it is possible to injure the needle seats. Note—16 notches equal a complete turn. 6 Open Pump Adjustment One Turn (16 notches). 7 Open Idling Adjustment One-half Turn (8 notches). 8 Open Intermediate Adjustment Two Complete Turns (32 notches). 9 Open High Speed Adjustment two and One-half Turns (40 notches). • NOW START THE ENGINE and WARM IT UP TO NORMAL OPERATING TEMPERATURE for the FINAL ADJUSTMENTS • 10 Idling Adjustment— Turn the idling adjustment to the leanest setting that will give steady and smooth running. If, after making this adjustment, the engine idles too fast or too slow, adjustment of the throttle stop screw will be necessary. 11 Throttle Stop Adjustment— (See Illus. D)—Turning throttle stop screw to the right (clockwise) gives faster idling; turning to the left gives slower idling. After making a change in the throttle stop adjustment, idling adjustment should always be rechecked. 12 Intermediate Adjustment— Be sure intermediate needle is set at trial adjustment of two complete turns or 32 notches. The intermediate adjustment should be made with the spark advanced and with the throttle partially opened. The throttle opening should be just enough to maintain an engine speed of about 2000 RPM’s or the equivalent of about 35 to 45 MPH car speed. Without changing the throttle opening, turn the intermediate adjustment to the right (leaner) two notches at a time, until the engine slows down very noticeably. As soon as a marked loss in engine speed is noticed, turn the adjustment to the left two notches (richer) at a time until there is no increase in engine speed, by richening the mixture. When this point is reached turn the adjustment to the right two notches at a time until a slightly perceptible slowing down of the engine is noticed. This is the correct intermediate adjustment. [ILLUSTRATION D with labels: THROTTLE ADJUSTING SCREW, LOCK NUT, THROTTLE STOP] 13 High Speed Adjustment— In order to set the high speed adjustment without making a road test, it is necessary to know the setting in notches of the intermediate adjustment. Since the trial setting on the intermediate was two turns (32 notches) this may easily be counted while the final intermediate adjustment is made by remembering the number of notches to the right or left the intermediate is turned, and subtracting or adding this from 32. If this procedure is not followed, the number of notches of opening of the intermediate adjustment will have to be counted after the final intermediate adjustment has been made. Be sure to turn it back to its correct setting. After determining the setting in notches of the intermediate needle an approximately correct setting for the high speed may be determined from the following table: 4 cyl. engines—4 to 6 notches more than Intermediate. 6 cyl. engines—8 to 12 notches more than Intermediate. 8 cyl. engines—12 to 16 notches more than Intermediate. If possible, the high speed adjustment should be checked by a road test. The leanest adjustment that gives full power and speed should be used. 14 Accelerating Pump Adjustment The pump adjustment governs the accelerating mixture. It operates just the reverse of the other three adjustments. Turning to the right gives a richer rather than leaner mixture. The richest accelerating mixture is obtained when the pump adjustment is screwed completely against its seat. This setting should rarely, if ever, be used. The leanest setting is obtained when the adjustment is open about three complete turns. The correct setting is usually about one-half to one and one-half complete turns open. The leanest pump adjustment setting that gives positive and smooth acceleration without hesitation or spitting back should be used. In cold weather a richer pump adjustment may be used to advantage than in hot weather. 15 Float Level— The float level has been correctly set at the factory and should not require changing. However, if unsatisfactory performance is experienced after all other adjustments have been properly made, the level should be checked. To do this, first have the car on level ground with engine idling. Then remove the float level inspection plug in front of the float bowl. The gasoline level should be just up to or slightly below the bottom edge of the inspection hole. If the gasoline is too far below the hole or out of sight, the level is too low. If it is above the bottom edge of the hole, it is too high. To change float level it is necessary to remove the float bowl cover. To raise float level, bend the float lever upward toward cover. To lower level, bend float lever downward away from cover. Do not make a change of more than 1/32 to 1/16” at one time. Replace cover, recheck level. NOTICE—In Blank Spaces Above Pictures Mark in the Settings of the Adjustments and Give Instruction Sheet to Car Owner | ||