we just got a brand new automatic 24hp john deere mower, and its been used, about 3 hours, and its starting to backfire when we turn the throttle down or turn it off.. why is this? do we need a new spark plug?
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john+deere
If the machine has a warranty on it **DO NOT WORK ON IT YOURSELF** you may void the warranty! Have the Deere Dealer pick it up and fix whatever is wrong with it! You have already paid hard earned money to have it repaired (with the purchase price) don’t gamble that money away! It is their job to have the machine ‘right’ for you!
john+deere
Number one, a brand new tractor shouldnt be backfiring. It could be running a bit rich, as manufacturers preset things like that. It could be little as bad gasoline ( from sitting before purchase).
Since, as suggested, it should still be under warranty- try seeing if the place you bot it from will see about fixing it. If it was from any home improvement store- good luck as they have to ship it out. I wouldnt mess with it , unless they give you some story about it bieng your fault or dont honor the waranty ( saying it doesnt fall under the warranty rules).
Good luck.