Lugging.. How much is OK?

[JimAStewart]

Thought I'd try mowing my hill the other day with my L2250 in high range, 1st gear (5th of 8). Had no trouble on the flat areas but when I headed up the hill, RPMs dropped off in a hurry. As soon as they dropped off I downshifted and had no problem. Realized then that never had any real previous limited horsepower experience. Here's the question. When the tractor starts lugging (dropping RPM), how much is too much?

Normally even in 4th gear I lose about 100 rpm climbing my hill (drops from 2350 to 2250 or so). Not sure how much of this is due the the speed control compensating for the increased load, or the actual affect of lugging.

Hopefully some of you out there with small compact tractors can shed some light on when to say when, definitely don't want to break anything [img]/w3tcompact/icons/smile.gif[/img].

TIA
Jim

[wen]

First Lugging is a term that needs more definition than I have seen for Diesels. In the good ol gasoline engine where there was low torque and low hp at low rpm and high torque at mid rpm and high hp at high rpm, you could easily get in a position where pushing on the accelerator did nothing. Pulling in this condition resulted in a retarted spark operation and the engine quickly overheated.

The normal way of operating tractors is to run in as high of a gear as is practical to pull the load and to back off the rpm where you can to minimize fuel consumption. This has limits if you are using the PTO and need to keep a constant rpm for the implements.

I suspect the engine is just running out of power and will drop off a little in rpm to get more torque to take you up the hill. This should not hurt anything if all you lose is 10% or so. More than that, just down shift and go on. The main gauge to watch is the temperature gauge If the temperature gauge starts climbing above normal, then you definately need to be running in a lower gear. I suspect you are running a hydro and the slippage builds quite a bit of heat and will quickly show up on the hydraulic lines (see if you can touch them - they get pretty hot) and in a couple of minutes in the water temperature gauge.

Since it is a Kubota, also stare hard at the oil pressure gauge [img]/w3tcompact/icons/wink.gif[/img].

[JimAStewart]

Wen, Thanks for the information. Sounds like my gut feeling that 50-150 rpm was OK but a rapid drop of 300-400 is probably a bad thing. The L2250 is not hydrostatic, so the pump thing shouldn't be a factor. I do keep an eye on the water temperature. The tractor only has an oil pressure idiot light. Not sure what you mean by "watch the oil pressure since its a Kubota." Perhaps I missed something in the previous discussions?

Again thanks

Jim

[wen]

No Kubotas have an oil pressure gauge. Always had to add them to my cars, but couldn't see any easy way to do that on the Kubota. I am sure the factory feels that an idiot light is better (and less expensive) for most folks.

As long as you stay in that range of rpm loss, you should have nothing to worry about. The main test is the engine temperature is running in the safe zone. Tractors are meant to do work, and they are capable of a lot more than most people ever call on them to do. There is an interesting article on the Texas Agricultural Extension Website concerning what they call shift up and rpm down to improve overall fuel consumption, which is what you are really doing, except the rpm is dropping for you. [img]/w3tcompact/icons/smile.gif[/img]