Mower deck LT4200 keeps throwing deck belt

OldChipper

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Jun 14, 2014
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a few years ago I purchased this Huskee 2010 LT4200 (MTD) 7 speed shift-on-the-go. Was in great shape, other than blown engine, seller said no one told him to change the oil??????? OK! Installed new engine. Has worked like a new one until this year. This year it keeps throwing the deck belt. Had never had this problem before. I've tried all brands of belts. I installed new spindles, both idler pulleys, all springs, brakes. (nothing else to replace) used only EOM parts. Could find nothing wrong with these parts I replaced. Pulley alignment appears okay. Anyone have any ideas!!
 

bertsmobile1

Lawn Royalty
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Nov 29, 2014
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Back to first principles.
Get some one to sit on the mower and turn the blades on & off.
Set the deck as low as you can ,
Lay on the left ( non discharge ) side and watch the belt jump off.
Put it back on and continue the cycles till you can identify exactly where the belt is jumping off.
IT could be some thing as simple as a belt keeper in the wrong position or strait fallen off.
You can download your parts book from Husqvarna so do that, print out the deck page and with the print out in hand, cross off all the keepers as you find them.

As this was a used & abused mower when you bought it the DPO could have done something like fitting a shorter belt to cover up another problem.
 
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