Cub Cadet SC 621 Operator'S Manual Download Page 19

19

Models SC 621 and SC 621E

Ref.

No.

Part No.

Description

Ref.

No.

Part No.

Description

1.

710-0134

Carriage Screw 1/4-20 x .62

44.

682-9024

Caster Bracket Assembly: RH

2.

710-0654A

Screw TT:3/8-18:1.00

45.

682-9026

Caster Bracket Assembly: LH

3.

710-0703

Carriage Screw 1/4-20 x .750

46.

711-1146

Caster Axle .374 Dia x 2.50” 

4.

712-0397

Wing Nut 1/4-20

47.

736-0232

Wave Washer

5.

723-0233

Push Nut .25 I.D. x .50 O.D.

48.

731-1888

Hub Cap w/ hole

6.

736-0204

Flat Washer .334 I.D.x .62 x.03

49.

734-1857

Wheel 7 x 2 Link

7.

782-0046A 

Deck - 21”

50.

712-0397

Wing Nut 1/4-20

8.

710-0653

Screw TT. 1/4-20 x .375

51.

734-1981

Wheel 9 x 2 Link 

9.

710-1220

Screw HL. 1/2-14 x .750

52.

712-3004A

Lock Nut 5/15-18

10.

731-1828

Baffle

53.

714-0104

Cotter Pin .072 x .12 Lg. 

11.

638-0012

Rear Axle Assembly

54.

736-0264

Flat Washer .330 x .830 x .060

12.

782-0566A

Pivot Arm Assembly

55.

10622B

Plastic Spring Ratchet

13.

682-7526

Transmission Axle Assembly

56.

748-0381

Pawl - R.H. 

14.

682-7528

Chain Cover Assembly

57.

748-0188B

Pawl - L.H. (Not Shown)

15.

710-0653

Screw TT 1/4-20 x .375

58.

16855

Ratchet Pawl Plate 

16.

710-0751

Cap Screw HH 1/4-20 x .620

59.

738-0137A

Screw Shoulder .340 x .285

17.

710-1652

Screw AB 1/4--20x.625

60.

712-0414

Top Lock Tab Weld Nut 1/4-20

18.

710-1315

Screw 3/8 116 x .25

61.

731-0982A

Hubcap,  w/o hole

19.

711-0835

Clevis  Pin .50 Dia. x 4.82 Lg.

63.

751B213146

Throttle Casing Clamp

20.

713-0453

Chain #48 .500P x 24L

64.

725-0157

Cable Tie

21.

714-0474

Cotter Pin .125O.D. x  .75

65.

710-0604

Hex Screw 5/16-18

22.

720-0223

Grip

66.

754-0460

Belt, 3/8”x 39.24”

23.

732-0803A

Spring Lever

67.

742-0741

21” Mulching Blade

24.

732-0832

Torsion Spring

68.

748-0377C

Blade Adapter

25.

736-0270

Bell Washer .285 x .75 x .082

69.

736-0524A

Blade Bell Support

26.

736-0369

Flat Washer .508 I.D. 1.000 x.020

70.

710-1257

Hex Bolt 3/8-24x2.5”Lg.

27.

738-0529

Shoulder Nut .825 Dia. x .165 Lg.

73.

731-1832

Side Discharge Chute

28.

741-0324

Hex Flange Bearing .506 I.D. x .590 L.

74.

731-1833

Mulch Cover

29.

741-0522

Hex Flange Bearing .506 I.D. x.715 L.

75.

726-0214

Push Cap

30.

741-0978

Hex. Sleeve Bearing .504 I.D. x .830 L.

76.

732-0306

Compression Spring

31.

748-0318

Wheel Rachet

77.

736-0366

Flat Washer .5/8 I.D. x 1” O.D.

32.

750-0151

Spacer .550 I.D. x /750 O.D.

78.

736-0931

Flat Washer .203 x .403 x .040

33.

750-0515

Spacer .51 .D. x .70 O.D. x 38 L.

79.

737-3000

Fitting - Grease

34.

750-0807

Spacer .385 x .624 x .700

80.

741-0685

Flange Bearing

35.

750-1056

Shoulder Spacer .385 I.D. x .715 Lg.

81.

747-0924

Locking Pin

36.

782-0568

Height Adjuster Spring Bracket 

82.

631-0066

Chute Ass’y

37.

682-3052

Handle Bracket Ass’y. R.H.

83.

731-1713A

Discharge Chute

38.

682-3053

Handle Bracket Ass’y. L.H.

84.

747-0965

Pivot Rod

39.

710-1348

Screw AB 1/4-14 x .500 

85.

732-0819

Torsion Spring

40.

731-1901

Trail Shield 

86.

726-0111

Push Cap

41.

732-0842

Trail Shield Wire

87.

731-1874

Chute Door

43.

682-9021A

Caster Assembly L.H.

88.

710-0260

Carriage Bolt 5/16-18 x.62

682-9020A

Caster Assembly R.H. (Not Shown)

NOTE:  For painted parts, please refer to
the list of color codes below. Please add the
applicable color code, wherever needed, to
the part number to order a replacement part.
For instance, if a part, numbered 700-xxxx,
is painted Cub Yellow,  the part number to
order would be 700-xxxx-0498.

Cub Yellow: 0498

Cub Beige: 0499

Powder Black: 0637

Summary of Contents for SC 621

Page 1: ...the engine s exhaust system is equipped with a spark arrester meeting applicable local or state laws if any If a spark arrester is used it should be maintained in effective working order by the operator In the State of California the above is required by law Section 4442 of the California Public Resources Code Other states may have similar laws Federal laws apply on federal lands A spark arrester ...

Page 2: ...eed help from our Customer Support Department or an authorized dealer You can locate the model number by looking down at the rear of the deck A sample model plate is explained below For future reference please copy the model number and the serial number of the equipment in the space below CALLING CUSTOMER SUPPORT If you have difficulty assembling this product or have any questions regarding the co...

Page 3: ...en overlooked and could be accidentally thrown by the mower in any direction and cause serious personal injury to the operator or any others allowed in the area Wear sturdy rough soled work shoes and close fitting slacks and shirts Shirts and pants that cover the arms and legs and steel toed shoes are recommended Do not wear loose fitting clothes or jewelry They can be caught in moving parts Never...

Page 4: ...e slope gauge Do not mow on wet grass Reduced footing could cause slipping CHILDREN Tragic accidents can occur if the operator is not alert to the presence of children Children are often attracted to the mower and the mowing activity Never assume that children will remain where you last saw them Keep children out of the mowing area and under the watchful care of a responsible adult other than the ...

Page 5: ...low objects to be thrown For safety protection frequently check components and replace with manufacturer s recommended parts when necessary Mower blades are sharp and can cut Wrap the blade s or wear gloves and use extra caution when servicing them Do not change the engine governor setting or overspeed the engine Excessive engine speeds are dangerous WARNING YOUR RESPONSIBILITY Restrict the use of...

Page 6: ... N T I N G A 1 5 S L O P E WARNING Do not mow on inclines with a slope in excess of 15 degrees a rise of approximately 2 1 2 feet every 10 feet A riding mower could overturn and cause serious injury If operating a walk behind mower on such a slope it is extremely difficult to maintain your footing and you could slip resulting in serious injury Operate RIDING mowers up and down slopes never across ...

Page 7: ...seated securely into the handle mounting brackets Tighten the wing nuts on each side of the handle carriage bolts must be seated properly into the handle See Figure 2 NOTE Your mower is shipped with the handle in the higher height position If you wish to lower the height of the handle refer to the Adjustment Section at this time Remove the hairpin clips from the outer hole in the weld pins on the ...

Page 8: ...er The blade control handle must be depressed in order to operate the unit Release blade control handle to stop engine and blade See Figure 6 WARNING This blade control mechanism is a safety device Never attempt to bypass its operations Rear Cutting Height Adjustment Lever The rear wheel cutting height adjustment lever is located above the left rear wheel The front wheel cutting height is determin...

Page 9: ...llowing questions With the drive clutch control released push mower forward and pull it backward Does it move freely Towards Better Mower Performance 1 Read this manual in its entirety before you start the lawn mower Instructions given here have been designed for maintaining safety while getting the best performance from your mower Follow the instructions closely 2 Pour fresh clean gasoline into t...

Page 10: ...rottle which is set at full throttle for best performance Stand behind the mower and squeeze the blade control handle against the upper handle Grasp recoil starter handle and pull rope out slowly until engine reaches the start of compression cycle rope will pull slightly harder at this point Let the rope rewind slowly Pull rope with a rapid continuous full arm stroke Keeping a firm grip on the sta...

Page 11: ...o move the starter rope out of the way of the bag when the chute door is opened Figure 9 Emptying the Grass Bag While holding the grass bag by both the rear handle and the lower handle lift the grass bag straight up off the adapter The chute door will move the rope out of the way of the bag Continue to hold the lower handle and raise the rear of the grass bag up toward your chest The grass bag wil...

Page 12: ...dle Height Adjustment Your mower is shipped with the handle in the higher height position To lower the height proceed as follows Remove the starter rope from the rope guide Remove the upper handle by removing the hand knobs and carriage bolts Lay the upper handle out of the way being careful not to bend or kink the cables Remove the hairpin clips from the weld pins on the handle brackets Press out...

Page 13: ...n the adjustable cable bracket and tighten hex nut Figure 15 Engine Adjustments See the separate engine manual packed with your unit for adjustments to the engine SECTION 7 MAINTAINING YOUR LAWN MOWER Adjustment Bottom View Wheel Drive Clutch Control Upper Handle Bottom View Speed Control Lever Upper Handle Hex Nut Adjustable Cable PUSH Bracket Customer Responsibilities MAINTENANCE SCHEDULE PRODUC...

Page 14: ...ausing a starting problem Engine Refer to the separate engine manual for all engine maintenance instructions Maintain engine oil as instructed in the separate engine manual packed with your unit Service air cleaner every 25 hours under normal conditions Poor engine performance and flooding usually indicate that the air cleaner should be serviced To service the air cleaner refer to the separate eng...

Page 15: ... your mower the blade bolt must be checked periodically for correct torque Drive Belt Removal and Replacement Disconnect the spark plug wire and ground it against the engine Drain the fuel tank or place a piece of plastic beneath the cap to prevent gasoline leakage Place shift lever in the first position and tip the mower on its side Remove the center bolt which secures the blade to the crankshaft...

Page 16: ...so that the belt is not in the pulley groove and the lower pulley can be pushed towards the engine See Figure 22 Pivot the control arm back to its original position and reinstall the six speed cable into the slot See Figure 23 Check and make sure the belt is routed inside the pulley halves and the belt guard pin Figure 23 Reinstall the bolt securing transmission to rear mower housing Transmission ...

Page 17: ...ected 3 Fuel tank empty or stale fuel 4 Blocked fuel line 5 Faulty spark plug 1 Engage blade control handle 2 Connect wire to spark plug 3 Fill tank with clean fresh gasoline 4 Clean fuel line 5 Clean adjust gap or replace Engine runs erratic 1 Spark plug wire loose 2 Blocked fuel line or stale fuel 3 Vent in gas plugged 4 Dirty air cleaner 5 Carburetor out of adjustment 1 Connect and tighten spar...

Page 18: ...ference only 41 40 65 36 24 17 21 19 34 18 13 28 26 32 29 11 20 26 28 35 12 14 15 30 33 26 31 25 16 27 23 22 64 38 7 66 2 2 37 39 60 51 58 55 59 61 56 16 25 31 4 5 73 4 5 74 87 85 86 84 83 82 9 9 8 10 8 68 68 67 69 70 48 49 48 81 78 79 76 54 53 46 47 50 44 45 52 77 80 43 80 77 75 6 1 3 6 2 88 ...

Page 19: ...39 24 23 732 0803A Spring Lever 67 742 0741 21 Mulching Blade 24 732 0832 Torsion Spring 68 748 0377C Blade Adapter 25 736 0270 Bell Washer 285 x 75 x 082 69 736 0524A Blade Bell Support 26 736 0369 Flat Washer 508 I D 1 000 x 020 70 710 1257 Hex Bolt 3 8 24x2 5 Lg 27 738 0529 Shoulder Nut 825 Dia x 165 Lg 73 731 1832 Side Discharge Chute 28 741 0324 Hex Flange Bearing 506 I D x 590 L 74 731 1833 ...

Page 20: ...20 Model SC 621E 16 21 18 20 23 22 17 19 24 A 26 25 A 28 27 29 14 30 2 2 4 36 3 5 1 5 3 7 6 34 33 31 32 35 39 40 56 12 11 42 41 46 38 50 54 47 44 45 51 37 53 49 52 55 ...

Page 21: ...16 731 0904A Upper Control Housing 41 725 0873 Ignition Switch 17 731 0924 6 Speed Shift Lever 42 725 0201 Ignition Key 18 713 0397 Gear Insert 44 725 1206 Plug 19 710 1667 C Sunk Tap Screw 10 16x 625 45 625 0021 Wire Harness 20 732 0627 Shift Lever Spring 46 710 1270 Hex Bolt 1 4 20 x 1 3 Lg 21 16864 6 Speed Rack Cable Brkt 47 736 0270 Bell Washer 1 4 I D 22 731 0905A Lower Control Housing 49 782...

Page 22: ...22 Model SC 621 16 21 18 20 23 22 17 19 24 A 26 25 A 28 27 29 11 13 14 15 30 2 2 4 36 3 5 1 5 3 34 33 31 32 35 37 6 8 ...

Page 23: ...37 736 0451 Saddle Washer Ref No Part No Part Description Model SC 621 Ref No Part No Part Description 1 710 1174 Carriage Bolt 5 16 18 x 2 0 2 714 0104 Cotter Pin 072 x 1 12 Lg 3 720 0241 Knob Ass y Wing Nut 5 16 18 4 726 0240 Strap 4 3 Lg 5 736 0451 Saddle Washer 320 ID x 830 OD 6 712 0429 Hex Nut 5 16 8 710 1270 Oval C Sunk Screw 11 712 0324 Lock Nut 1 4 20 13 746 0883 Control Housing 14 746 09...

Page 24: ...x 75 x 062 9 736 0329 Lock Washer 1 4 Reg Duty 10 736 0526 Wave Washer 1 38 x 88 x 029 11 738 0924 Shoulder Screw 375 x 1 4 14 12 750 1070 Sleeve Spacer 88 ID x 1 00 OD 13 750 1071 Sleeve Spacer 88 ID x 1 13 ID 14 756 0625 Roller Cable 15 782 7574 6 Speed Cable Adj Bracket 16 782 7575 6 Speed Cable Mt Bracket 17 782 7596 6 Speed Control Arm 18 782 7597 6 Speed Pivot Bracket 19 712 0138 Hex Nut 1 4...

Page 25: ...0 Flat Washer 885 x 1 45 14 721 0329 Oil Seal 15 618 0253 Upper Housing Assembly 16 736 0616 Thrust Washer 504 x 70 17 717 1487 Pinion Shaft 10T 18 736 0314 Thrust Washer 3 8 x 70 19 736 0569 Thrust Washer 388 x 625 20 618 0252 Lower Housing Assembly 21 710 0642 Hex Screw 1 2 20 x 75 22 782 7601A Cable Bracket 23 741 0674 Bearing 24 611 0066 Shaft Assembly 25 721 0325 Plug 26 717 1469 Gear 34T 27 ...

Page 26: ...26 NOTES ...

Page 27: ...27 ...

Page 28: ...adet equipment used commercially is warranted for one year only Commercial use is defined as either having hired operators or used for income producing purposes Items not covered The warranty does not cover routine maintenance items such as lubricants filters oil fuel air and hydraulic cleaning tune ups brake and or clutch inspection adjustments made as part of normal maintenance blade sharpening ...

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