# Belt flipping Craftsman LT2000



## Stephen Webb (Dec 21, 2019)

Anyone know what would cause the deck belt to flip over in the pulleys? I;ll correct it and run for a few minutes and it flips over.


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## Bob Driver (Nov 1, 2017)

Get the mower on level concrete and lower the deck as far as possible without the anti-scalp rollers touching the floor. Odds are 90%, the left side of the deck is going to be lower than the right side. With the torque/rotation of the engine, the belt coming off the left side of the deck is being "pulled" towards the drive pulley on the engine. Once it passes over the drive pulley it's being "pushed" at the deck pulley and it has a tendency to twist if the deck is not side-to side level. That's why most decks have a flat tensioner pulley as the first pulley in the belt routing on the right side. It's to keep the belt from "flailing" as it comes off the drive pulley. Get somebody to sit on the seat (or by-pass the seat safety switch) and engage the deck, watch to see how much the belt "flails" between the drive pulley and the tensioner pulley(you'll see what I mean). Check to see that the flat tensioner pulley is not froze up by rust, or debris, and still has spring-loaded tension. The most common reason the deck gets out of side-to side level is that it gets stepped on with the operator getting on/off the mower(everybody does it).

Place two stacked 2x4's on each side of the deck and lower it until the deck rest solidly on both stacks. Use those stacked 2x4's like a 3" feeler gauge to adjust the deck to side-to-side level and calibrate the height control lever to seat perfectly in the 3" notch. The machine will actually give you the best looking cut with the front of the deck at 3" and the rear slightly higher at 3 1/4".

V-belts don't like running with more than 30 degrees of deflection angle to a pulley groove. Most OEM"s design the deck belt to run the straightest alignment with the drive pulley when the deck height is set at 3 inches. When you start dropping the deck height down to 2" or lower, you start to exceed that 30 degree deflection angle from the drive pulley and the belt likes to either twist, or derail with the slightest change in blade rotation speed due to encountering thicker grass. The problem is compounded by a worn belt, or a worn/damaged drive pulley groove. Drop the deck all the way down to the lowest height possible and you'll see what I mean by belt deflection angle.


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