Drain the gasoline from the snow thrower, or place a piece of plastic film under the gas cap.

Tip the snow thrower up and forward so that it rests on its auger housing.

Remove the six self-tapping screws from the frame cover underneath the snow thrower.

Roll the front and rear auger belts off the auger drive pulley. See Figure 17.

Unhook the idler spring from the hex bolt on the auger housing. See Figure 18.

Back out the stop bolt until the support bracket rests on the auger pulley.

NOTE: Loosening the six nuts that connect the frame to the auger housing may aid in belt removal.

 

Drive

 

Pulley

Auger

Drive

Pulley

Belt

Idler

Idler

Pulley

Pulley

 

Auger

 

Belts

 

Frame

Figure 17

Lift the rear auger belt from the auger pulley, and slip the belt between the support bracket and the auger pulley. Repeat this step for the front auger belt.

Replace both auger drive belts by following instructions in reverse order.

Friction

 

Wheel

 

Support

Support

Bracket

 

Bracket

 

Spring

Auger Pulley

Auger Housing

 

Idler Spring

Figure 18

NOTE: If you placed plastic film under the gas cap, be certain to remove it before operating the snow thrower

Drive Belt

Follow the first four steps of the instructions for servicing the auger belts.

Pull the idler pulley up and lift the belt off the wheel drive pulley and friction wheel disc. See Figure 17.

Back out the stop bolt until the support bracket rests on the auger pulley. See Figure 19.

Friction

 

Wheel

Drive Plate

 

Stop Bolt

 

Support Bracket

Auger Pulley

 

Figure 19

Slip the belt between the friction wheel and drive disc. Remove and replace the belt. Reassemble following the instructions in reverse order.

NOTE: The support bracket must rest on the stop bolt after the new belt has been assembled.

Replacing Friction Wheel Rubber

The rubber on the friction wheel is subject to wear and should be checked after 25 hours of operation, and periodically thereafter. Replace the friction wheel rubber if any signs of wear or cracking are found.

Drain the gasoline from the snow thrower, or place a piece of plastic under the gas cap.

Tip the snow thrower up and forward, so that it rests on the housing.

Remove the six self-tapping screws from the frame cover underneath the snow thrower.

Remove the click pin that secures the left wheel to the axle and slide the wheel from the axle.

Using a 7/8" wrench to hold the shaft, loosen, but do not completely remove, the hex nut and bell washer on the left end of gear shaft. See Figure 20.

Lightly tap the hex nut to dislodge the ball bearing from the right side of frame before removing the hex nut and bell washer from left end of shaft.

Move the gear shaft to the right and slide the friction wheel assembly from the shaft.

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MTD 663, 643 manual Replacing Friction Wheel Rubber, Drive Belt