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10

With the traction control released, there must be 
clearance between the friction wheel and the drive 
plate in all positions of the shift lever. 

With traction control engaged, the friction wheel 
must contact the drive plate. See Figure 9.

Figure 9

If adjustment is necessary:

Loosen the jam nut on the traction drive cable and 
thread the cable in or out as necessary. 

Retighten the jam nut to secure the cable when 
correct adjustment is reached. 

Reassemble the frame cover.

NOTE: 

If you placed plastic film under the gas cap, be

certain to remove it before operating the snow thrower. 

Auger Control

Refer to details on page 6 to adjust the auger control.

Shift Rod 

To adjust the shift rod, proceed as follows.

Remove hairpin clip and slide shift rod connector 
up to separate upper and lower shift rod. See 
Figure 10.

Place shift lever in sixth (6) position or fastest 
forward speed.

Rotate shift arm assembly counter clockwise as far 
as it will go.

Thread the upper shift rod on the ferrule to align 
upper shift rod elbow with lower shift rod hole.

Insert cotter pin and slide shift rod connector down. 
Tap to secure the connector into place.

IMPORTANT:

  Check for correct adjustment of the shift 

lever rod as instructed on page 6, before operating the 
snow thrower.

Figure 10

Drive Wheels

The wheels may be adjusted for two different methods 
of operation. The adjustment is made by placing the 
click pins in one of two different holes on the right side 
of the unit. See Figure 11.

One Wheel Driving: 

Insert the click pin only 

through the outside hole of the axle (not the rim) on 
the right side of the snow thrower. This position 
gives power drive to the left wheel only, making the 
unit easier to maneuver.

Both Wheels Driving: 

Insert the click pin through 

the hole in the hub of the rim and the inside hole on 
the snow thrower’s right axle. This position is good 
for heavy snow as there is power drive in both 
wheels.

Figure 11

IMPORTANT:

 Never operate the snow thrower with the 

click pin inserted through both the rim and the outside 
hole in the axle. Doing so can result in serious damage 
to the drive system.

Friction

Wheel

Gear Shaft

Drive
Plate

Shift
Lever

Ferrule

Upper
Shift Rod

Hairpin
Clip

Shift Rod
Connector

Lower
Shift Rod

Shift Arm
Assembly

Inside Hole

in Axle

Click Pin 

in Outside Hole

Summary of Contents for 640

Page 1: ... 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 for the muffler is available through your nearest engine auth...

Page 2: ...orized dealer You can locate the model number by standing behind the unit in the operating position and looking down at the rear frame below the engine 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 regard...

Page 3: ... the auger impeller 2 Always wear safety glasses or eye shields during operation and while performing an adjustment or repair to protect your eyes Thrown objects which ricochet can cause serious injury to the eyes 3 Do not operate without wearing adequate winter outer garments Do not wear jewelry long scarves or other loose clothing which could become entangled in moving parts Wear footwear which ...

Page 4: ...d Storage 1 Never tamper with safety devices Check their proper operation regularly 2 Disengage all clutch levers and stop engine Wait until the auger impeller come to a complete stop Disconnect the spark plug wire and ground against the engine to prevent unintended starting before cleaning repairing or inspecting 3 Check bolts and screws for proper tightness at frequent intervals to keep the mach...

Page 5: ...e 1 and align with lower handle Figure 1 NOTE Make sure cables are set in the cable roller guides in the lower rear of the snow thrower Secure the upper handle to the lower handle with the hardware removed earlier Adjust eyebolt on the chute directional control so the control rod does not contact the engine Move the hex nut against the handle in order to adjust Retighten the wing nut to secure the...

Page 6: ...you can depress the auger control against the left handle completely If necessary loosen the hex jam nut and thread the cable in for less slack or out for more slack as necessary Recheck adjustment Tighten jam nut when correct adjustment is reached See Figure 5 Figure 5 Traction Control and Shift Lever To check the adjustment of the traction control and shift lever move the shift lever all the way...

Page 7: ...directional control without interrupting the snow throwing process If the auger control is engaged with the traction control engaged the operator can release the auger control on the left handle and the augers will remain engaged Release the traction control to stop both the augers and wheel drive auger control must also be released Chute Directional Control The chute directional control is locate...

Page 8: ...y for first start if temperature is below 15 degrees Fahrenheit Grasp starter handle and pull rope out slowly until it pulls slightly harder Let rope rewind slowly Pull starter handle rapidly Do not allow handle to snap back Allow it to rewind slowly while keeping a firm hold on the starter handle Repeat step above until engine starts As engine warms up and begins to operate evenly rotate choke kn...

Page 9: ...thrower will move Release it and unit will stop Never move shift lever without releasing traction control To Engage Augers To engage augers and start throwing snow squeeze the auger control against the left handle Release to stop the augers Tire Chains Optional Equipment Tire chains should be used whenever extra traction is needed If your unit is not equipped with tire chains you may purchase them...

Page 10: ...nsert cotter pin and slide shift rod connector down Tap to secure the connector into place IMPORTANT Check for correct adjustment of the shift lever rod as instructed on page 6 before operating the snow thrower Figure 10 Drive Wheels The wheels may be adjusted for two different methods of operation The adjustment is made by placing the click pins in one of two different holes on the right side of ...

Page 11: ...ism Remove rear cover Oil any chains sprockets gears bearings shafts and shifting mechanism at least once a season Use engine oil or a spray lubricant Avoid getting oil on rubber friction wheel and aluminum drive plate Gear Case The worm gear case has been filled with grease at the factory If disassembled for repairs lubricate with 2 ounces of shell grease part no 737 0168 IMPORTANT Do not overfil...

Page 12: ...w shave plate making sure heads of the carriage bolts are to the inside of the housing Tighten securely Belt Replacement WARNING Disconnect the spark plug wire from the spark plug and ground Auger Belts NOTE It is necessary to remove both belts in order to change either one If changing just one belt be certain to check the condition of the other belt Remove the plastic belt cover in front of the e...

Page 13: ...ecure the wheels and remove the wheels from the axle Using a wrench to hold the shaft loosen but do not completely remove the hex nut and bell washer on left end of gear shaft See Figure 18 Lightly tap the hex nut to dislodge the ball bearing from the right side of frame Remove the hex nut and bell washer from left end of shaft Slide the gear shaft to the right and slide the friction wheel assembl...

Page 14: ...esh fuel Refer to the engine manual packed with your unit or have carburetor adjusted by an authorized service dealer Loss of power Spark plug wire loose Gas cap vent hole plugged Exhaust port plugged Connect and tighten spark plug wire Remove ice and snow from cap Be certain vent hole is clear Clean see Maintenance section of engine manual Engine overheats Carburetor not adjusted properly Incorre...

Page 15: ...17 0528 Worm Gear 20T 8 717 0526 Worm Shaft 9 718 0186 Thrust Collar 10 721 0325 Grease Plug 11 721 0327 Grease Seal 12 736 0351 Flat Washer 76 x 1 5 x 030 13 736 0369 Flat Washer 508 x 1 0 x 020 14 736 0445 Flat Washer 76 x 1 5 x 060 15 741 0662 Flange Bearing 75 x 1 0 x 59 16 741 0663 Flange Bearing 75 x 1 0 x 925 17 618 0120A Ass y Complete 24 618 0121A Ass y Complete 26 618 0122A Ass y Complet...

Page 16: ...5 25 8 10 14 41 19 40 7 59 67 12 40 30 42 39 12 20 14 38 24 58 45 35 2 15 45 15 25 53 61 54 25 34 43 60 69 33 46 66 29 6 62 43 16 17 42 1 25 55 65 56 52 20 ITEM 21 GOES TO GROUND WIRE OF LIGHT ASSEMBLY 12 57 56 11 36 21 44 44 32 28 51 63 25 23 22 3 30 31 9 9 31 48 48 68 ...

Page 17: ...4 Wing Nut 32 726 0100 Push Cap 33 731 0851A Chute Flange Keeper 34 731 0921 Upper Chute 35 731 1300A Lower Chute 36 731 1393 Handle Panel 37 732 0145 Compression Spring 38 732 0193 Compression Spring 39 732 0746 Torsion Spring 40 735 0199A Bumper Rubber 41 736 0105 Bell Washer 401 x 870 42 712 3068 Hex Nut 5 16 18 43 736 0159 Washer 349 ID x 879 OD 44 736 0185 Flat Washer 375 ID x 738 OD 45 736 0...

Page 18: ...16 Wheels 13 or 15 Wheels 4 7 7 8 9 10 10 11 11 12 1 5 13 14 15 16 17 18 1 19 20 21 22 23 24 25 25 26 28 29 26 1 1 30 31 32 33 34 8 35 Drive Clutch Cable Auger Clutch Cable Auger Clutch Cable Blower Housing 36 20 20 37 37 38 39 40 27 ...

Page 19: ...0143 Klik Pin 27 684 0042B Friction Wheel Assembly 28 656 0012A Friction Disc Wheel 29 684 0013B Wheel Shift Rod Assembly 30 746 0897 Drive Cable 31 748 0190 Spacer 32 684 0021 Friction Wheel Bracket Assembly 33 732 0264 Extension Spring 34 712 0711 Jam Nut 3 8 24 35 746 0898 Drive Cable 36 738 0869 Axle 13 Wheels 738 0830 Axle 16 Wheels 37 784 5617A Friction Plate 38 735 0243B Friction Wheel Rubb...

Page 20: ... Lock Jam Nut 3 8 16 16 756 0569 Pulley Half 17 736 0242 Bell Washer 18 736 0505 Flat Washer 19 754 0430A Belt 20 756 0967 Auger Pulley 21 736 0247 Flat Washer 3 8 x 1 25 OD 22 736 0331 Bell Washer 23 710 0696 Hex Cap Screw 3 8 24 24 748 0360 Adapter Pulley 25 710 0654A Hex Screw 3 8 16 x 1 0 26 629 0071 Extension Cord 27 OEM 390 987 Electric Start REF NO PART NO DESCRIPTION 1 2 3 4 5 6 7 4 8 9 10...

Page 21: ...19 741 0475 Bushing 20 784 5647 Chute Crank Bracket 21 731 1379C Chute Adapter 22 712 0324 Hex Lock Nut 1 4 20 23 736 0463 Flat Washer 25 710 0703 Carriage Screw 1 4 20 x 75 26 710 0604A Hex Washer TT Screw 5 16 18 27 736 0169 Lock Washer 3 8 28 712 0798 Hex Nut 3 8 16 30 784 5580 Snow Shoe 31 736 0242 Bell Washer 32 712 3010 Hex Nut 5 16 18 33 784 5581A 24 Shave Plate 784 5579A 26 Shave Plate 784...

Page 22: ...22 YOUR NOTES Date Comment ...

Page 23: ...23 YOUR NOTES Date Comment ...

Page 24: ...y on these items b Hydraulic pumps valves and cylinders have a sepa rate one year warranty c Routine maintenance items such as lubricants filters blade sharpening and tune ups or adjustments such as brake adjustments clutch adjustments or deck adjustments and normal deterioration of the exterior finish due to use or exposure d MTD does not extend any warranty for products sold or exported outside ...

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