Shift Up And Throttle Down To Save Fuel Advises LSU AgCenter Engineer

News You Can Use For September 2005

As fuel prices rise, tractor owners are looking for ways to reduce fuel consumption. Dr. Richard Parish, an engineer with the LSU AgCenter’s Hammond Research Station, has some suggestions for saving fuel.

Parish says that shifting to a higher gear and reducing engine rpm when performing such light-duty operations as mowing grass or making hay sometimes can reduce fuel consumption.

Although tractors are often run at a high engine rpm to give the rated power-take-off (PTO) speed, Parish says this speed is not necessary if the PTO is not in use.

"Shifting up and throttling back can give the same ground speed while the engine works harder but at a lower rpm, thus operating more efficiently and consuming less fuel per hour or per acre," he says.

This process is normally not practical when using PTO implements, since the PTO shaft should turn at the rated speed of 540 rpm (or 1,000 rpm on larger tractors) for proper implement operation. Some tractors, however, have a two-speed PTO that provides 540 rpm on the PTO at two different engine speeds.

"Using the lower engine speed to provide 540 rpm on the PTO is more efficient if you do not need full power," Parish says. "You must avoid increasing engine speed too much while using this PTO setting to avoid overspeeding the PTO."

He says some current tractors have an interlock built in to prevent PTO overspeeding under this situation.

Parish says shifting up and throttling back is an easy way to reduce fuel consumption if you are not using the PTO or if your tractor has a two-speed PTO.

For related equipment topics, go to the LSU AgCenter Web site, Additional yard and garden information is available from an extension agent in your parish LSU AgCenter office.


On the Internet: LSU AgCenter:
Source: Dick Parish at (985) 543-4125 or
Writer: Rick Bogren at (225) 578-5839 or

9/23/2005 2:41:09 AM
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