Service and Parts Manual - Cummins Onan

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ARBURETOR ADJUSTMENTS he carburetor has a main fuel valve adjusting screw id an idle valve adjusting screw (Figure 7). A low xed adjustment screw is shown in Figure 8. :itiaI Adiustment: 1. Turn main fuel valve clockwise until it just closes. CAUTION Do not open main fuel jet more Ez3 than 1/2 turn beyond the maximum power point as this could cause spark plug fouling etc. 2. Now open main fuel valve 2 turns counterclockwise. 3. Close idle valve insame manner and open it one turn (counterclockwise). 1. This initial adjustment will permit engine to start and warm up prior to final adjustment. SET LOW SPEED ADJUSTMENT SO ENGINE RUNS A T 1200 RPM IN "SLOW" POSITION. FlGURE 8. LOW SPEED ADJUSTMENT LOW SPEED SET ON GOVERNOR LINKAGE- SMALL GAP HERE AT NO LOAD SIDE VIEW THRO~TLE STOP SCREW MAIN FUEL (HIGH SPEED) ADJUSTMENT IDLE ADJUSTMENT REAR VIEW GOVERNOR (Figure 9) These engines are adapted for use where a wide range of speed settings is desired. Engine speed is controlled at any given point between minimum and maximum by simply shifting the throttle lever on the dash panel until the desired speed is reached. The design of the variable speed governor gives an automatic decrease in sensitivity when the speed is increased and the result is good stability at all speeds. A reliable instrument for checking engine speed is required for accurate governor adjustment. Engine speed can be checked with a tachometer. FIGURE 7. MAIN FUEL AND IDLE VALVE ADJUSTMENT ?no1 Adiustment: . Turn main fuel valve in until engine misses (lean mixture), then turn it out past the point where engine runs smoothly until engine runs unevenly (rich 'mixture). Turn valve to mid-point between lean and rich so engine runs smoothly. . Hold engine at idle position and set low speed adjustment screw (Figure 8) until a fast idle is obtained (1200 rpm). . Hold throttle in idle position and turn idle adjustment valve in (lean) and out (rich) until engine idles smoothly. . Reset low speed adjustment screw so engine idles at 1200 rpm. . Release throttle - engine should accelerate without hesitation. If engine does not accelerate properly, readjust main fuel valve by turning out slightly. Important: Do not open more than 1/2 turn beyond maximum power point. Check the governor arm, linkage, throttle shaft, and lever for binding condition or excessive slack and wear at connecting points. A binding condition at any point will cause the governor to act slowly and regulation will be poor. Excessive looseness can cause a hunting condition and regulation will be erratic. Work the arm back and forth several times by hand while the engine is idling to check for above conditions. If governor is hunting or not operating properly, adjust as follows and as shown in Figure 9. 1. Disconnect linkage (A) from one of holes (C). 2. Push linkage (A) and governor arm (B) as far back (toward carburetor) as they will go. 3. Holding linkage and governor arm toward direction of Carburetor, insert end of linkage into whichever hole (C) (in governor arm) lines up the closest. The governor control spring is factory set in the top or second hole of the governor arm (farthest from pivot). To increase the sensitivity, move the spring loop into the hole nearest the pivot point or shaft. To decrease the secsitivity, move the spring outward. After the sensitivity has been set, adjust the low speed with the adjustment screw on the control wire bracket. 10
Y THROTTLE PLATE @ GOVERNOR CONT GOVERNOR AIR CLEANER -If air cleaner becomes too dirty, engine will not receive sufficient air to run properly. Symptoms: Loss of power, flooding, hard to start and overheating. Engine is equipped with a paper element. If the engine is equipped with polyurethane precleaner, it must be removed, cleaned and oiled every 25 hours of operation, or more under extremely dusty conditions. 1. To clean precleaner wash in water and detergent referring to Figure 10. Remove excess water by squeezing like a sponge and allow to dry thoroughly. Distribute three tablespoons of SAE 30 engine oil evenly around the precleaner. Knead into and wring excess oil from precleaner. 2. Depending on conditions in which the tractor is operating, the inner paper element should be replaced whenever it becomes excessively dirty or oily. Never run the engine with the air cleaner removed. Dirt will enter the engine and. wear out the rings causing excessive blow-by. FIGURE 9. GOVERNOR ADJUSTMENTS 1. WASH 2. SQUEEZE DRY 3. COAT WITH OIL 4. INSTALL OVER PAPER ELEMENT OLY URETHAN E: PRE CLEANER . BREATHER HOSE INTAKE TUBE FIGURE IO. AIR CLEANER ASSEMBLY 11
Page 1 and 2: 965-0250 12-87 (SPEC A-F) Printed i
Page 3 and 4: J , SERVICE MANUAL TABLE OF CONTENT
Page 5 and 6: SPEC1 FI CATIONS Engine Manufacture
Page 7 and 8: ENGINE TROUBLESHOOTING 5
Page 9 and 10: HEX HEAD CAP SCREW ,a I OIL PUMP IN
Page 11: PUMP COVER i w EXPLODED VIRN.OF FUE
Page 15 and 16: This engine uses a I2 volf, negativ
Page 17 and 18: STARTING SYSTEM ELECTRIC STARTER (S
Page 19 and 20: . n I NOTE. &incry a, smer wire siz
Page 21 and 22: h Tappet Adiustmment: The engine is
Page 23 and 24: CRANKSHAFT GEAR RKS MUST WHEN IN- T
Page 25 and 26: FIGURE 33. MEASURING PISTON CLEARAN
Page 27 and 28: CRANKSHAFT Inspect the bearing jour
Page 29 and 30: \\hen installing the gear cover oil
Page 31 and 32: INTRODUCTION . This catalog applies
Page 33 and 34: 2 6 REF. NO. 1 2 3 4 5 6 1. 9 10 11
Page 35 and 36: REF. PART OTY. PART- NO. NO. USED M
Page 37 and 38: GEARCASE, OIL BASE AND OIL PUMP REF
Page 39 and 40: FUEL SYSTEM REF. PART NO. NO. 1 140
Page 41 and 42: CARBURETOR PARTS L REF. PART QTY. P
Page 43 and 44: ALTERNATOR, AIR HOUSING, GOVERNOR A
Page 45 and 46: STARTER PARTS - SPEC A REF. NO. PAR
Page 47 and 48: c OPTIONAL EQUIPMENT PARTS SECTION
Page 49 and 50: OPTIONAL GROUP NUMBER 2 TOPADJUSTED
Page 51: OPTIONAL GROUP NUMBER 3 'CARBURETOR

Service and Parts Manual - Cummins Onan

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