John Deere Maintenance Monday: Lawn mower: Flushing the gas tank

When your lawn tractor starts idling rough and won't go into full throttle, it maybe a problem in the gas tank.

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In this edition of Maintenance Monday, we're answering a question from Vic in New York. His lawn tractor has been running fine all summer, but now it idles rough and won't go to full throttle. He peeked into the gas tank and saw bits of sediment on the bottom, could that be the problem? Walter Tubbs is a John Deere Ag Tech Instructor at Arkansas State University-Beebe (bee-bee). He says yes, the gas may be the culprit, especially if people fill lawn tractors from gas cans. "When they do that, they're introducing water and contaminants into that system because even though the pumps at the station have filters and stuff on them, you're going to get a certain amount of dirt and debris in your fuel container regardless of how clean you are," he says. "Over a period of time that can build up, hopefully it will catch it in your fuel filter." Most fuel filters are clear and visible from the outside of the lawn tractor. Look to see if there is sediment or water in the filter. Water will settle out and form into a ball within the fuel. Tubbs says flushing the gas out of the entire system may get the gunk out. "What you can do is just take the line going into the bottom of the tank off, or follow the line out until you find a joint under that connection and let the gas drain out," says Tubbs. "You may want to take a flashlight and look down in there to see how much more is in there, and you may want to try to flush the system. Leave the line off and pour a little bit of gas in there to see what you can flush out without having it sit in the tank." Tubbs says if Vic sees a water ball in the fuel filter, he should take the bottom bowl off the carburetor, wipe it out, and put it back on. There might be some air in the system after flushing, and it could take some cranking to prime it up to where the carburetor fills with fuel and the engine will run.

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