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How to adjust blades and deck height on Craftsman 42" Lawn Tractor?

Craftsman Lawn Tractor, 20.0 HP 42" Mower
Model No. 917.288110

1. I changed blades to Mulching Blades #7133178 and when I disengage the blades I can hear them clanging on something as they are slowing down. Do they need to be positioned in a certain way? They are securely on the star center.

2. Also, when adjusting the deck - how high should the deck be from the ground in highest position and lowest position. In other words; for each number I can adjust it to what is the height of the deck from the ground?

Thanks for your help.

Craftsman , Lawn Mowers , Lawn Tractors
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2 Answers from these members:
Mark T
Thank you for your question.

I am sorry you are having a problem with the tractor. I have looked up the model number and the part number for the mulch blade is 134149. I looked for the blade number you have submitted but I could not find any information on it. I am thinking you might have gotten the wrong blades if the problem developed after replacing the blades. If you have the old set of blades, you can check the length of the new blades. If they are the same length, turn the blades by hand to make sure they are not hitting the housing or each other. If you find one or both of them, hitting double check to make sure the blade is on the star of the mandrel.

The numbers for the deck height are just for reference not inches. You can set the deck to the highest position and measure from the blade tip to ground. Then use a permanent maker to write inches next to the number. I had to do this with my mower.

Please let me know if you need further assistance with the tractor.

If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website:

Sears Home Services


Thank you for using Manage my life.

Mark T.
by Mark T Earned 1,649 community points in Craftsman
May 12th, 2011
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