Cummins/Onan — SPEED ADJUSTMENT NUT - SENSITIVITY ADJUSTMENT

For these Cummins/Onan models: NHE-NHEL, NHE/NHEL RV.

Applies to: Cummins Onan Nhe Nhel

Procedure

1. The carburetor fuel mixture screws must be cor- rectly adjusted before governor adjustments are made. If the carburetor needs adjusting, refer to Mixturescrew Adjustments in this section before making any adjustments to the governor. Touching hot exhaust pipes or IBWAR"G/ moving parts can result in severe personal injury. Use extreme caution when making adjustments while the engine is running. Reed valve must be assembled as shown with washer on top and breather baffle on the bottom.
2. Adjust the length of the governor linkage and check for bindina or excessive looseness. The - 1 Over tightening the valve cover can cause an air leak and allow dirt to enter the engine. Be careful not to distorf the valve cover when tightening. GOVERNOR The governor controls engine speed which directly affects the voltage output and frequency of the generator. An increase in enginezipeed will cause a corresponding increase in generator voltage and fre- quency. A decrease in engine speed will cause a corresponding decrease in generator voltage and length of the liniage connecting the governor arm to the throttle shaft assembly is adjusted by loosening the lock nut and rotating the ball joint (see Figure 6-11). Adjust this length so that with the engine stopped and tension on the governor spring, the stop on the throttle shaft assembly almost touches the stop on the side of the car- buretor. (One more turn of the governor ball joint would allow the throttle shaft stop to touch the carburetor.) Tighten lock nut.
3. With the warmed up unit operating no no load, adjust the speed adjustment nut to obtain 62 hertz and 127.5 (~k4.5) volts for frequency and voltage. 6-1 1 Redistribution or publication of this document, by any means, is strictly prohibited.
4. Check the frequency and voltage first with a load applied and then with no load applied. The fre- quency and voltage should stay within the limits shown in Table 6-1. TABLE 6-1. VOLTAGE AND SPEED CHARTS VOLTAGE CHART FOR CHECKING 1 PHASE Maximum 132 Minimum 108 GOVERNOR REGULATION 2 WIRE No-Load Voltage Full-Load Voltage SPEED CHART FOR CHECKING GOVERNOR REGULATION Maximum No-Load Speed (Rpm) 1890 Hertz (Frequency) 63 Minimum Full-Load Speed 1770 (Rpm) Hertz 57
5. Adjust the governor sensitivity to give the closest regulation (least speed and voltage difference between no load and full load) without causing a hunting condition. To increase sensitivity (closer regulation), turn the sensitivity adjustment screw counterclockwise. To decrease sensitivity, turn the sensitivity adjustment screw clockwise. SPEED ADJUSTMENT NUT - SENSITIVITY ADJUSTMENT SCREW FS-1613 FIGURE 6-11. GOVERNOR ADJUSTMENTS
6. Recheck the speed setting made in step #3 and
7. Set thecarburetor throttlestop screw as specified readjust if necessary. in the Fuel System section. FUEL SYSTEM - GASOLINE The fuel system must be in good condition and prop- erly adjusted for efficient generator set operation. The main components of the fuel system are the air cleaner assembly, carburetor, choke, intake mani- fold, fuel filter, fuel pump, and air preheater. When servicing, disassemble, assemble, and adjust as spec- ified in the following sections. Air Filter Assembly The air filter assembly consists of the air cleaner housing, air filter, air cleaner adapter, and choke assembly (See Figure 6-12). Disassembly: Use the following procedures to remove and disassemble the air filter assembly.

Source: manual:940-0502 Onan NHE-NHEL (spec A-C) RV Genset Service Manual (07-1987).pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.