l4060 - Sudden, very brief drop in RPM when very slowly moving in to pick up a unit of lumber with forks

[Jim Goodman]

I just bought a 2016 L4060 HST with 170 hours on it. I have only used it for a couple of hours. It replaces an L48 TLB I sold, so this is my first Tier 4 machine.

I have some units of hardwood lumber I need to move to a different location on my property. Yesterday I was moving a stack that consisted of 3 separate units, stacked on top of each other with stickers separating each unit. I was very, very slowly creeping forward with my SSQA forks to slide the forks into the space between the top unit of lumber and one below it. I had not yet lifted or curled the forks. There was no load yet on the forks, at all. I'm running the engine at 2000 rpm so I don't clog up the DPF......I'm not letting it idle except for when I start the motor. So, I was operating it for about 5 minutes at 2000 rpm before I went to move that unit of lumber. As I was creeping in and just about ready to pick up the lumber, the rpm dived to idle speed and the machine stopped moving. I wasn't using the auto-throttle. I was manually setting the throttle speed with the throttle lever. When the rpm dropped I let off on the foot pedal so it went back to the neutral position and the motor sped back up to 2000 rpm. I stepped on the foot pedal and the motor dropped to idle again. This routine repeated a couple more times. I then pushed the throttle lever up to 2600 rpm and I was able to continue working without the rpm diving.

Can anybody tell me what's going on with this and am I doing something wrong? No error messages or lights are coming on when this happens. It happened twice yesterday, but I also picked up units of lumber where it did not happen. I'm clueless as to why this is happening. Thanks.

 

[85Hokie]

First thing that comes to mind is a fuel delivery problem - then again with the way that system works (auto throttle) it may not be that.

When was fuel filters changed last?

 

[johnsayen]

Could it be the stall guard?

 

[Jim Goodman]

First thing that comes to mind is a fuel delivery problem - then again with the way that system works (auto throttle) it may not be that.

When was fuel filters changed last?

I bought it from a dealer and it was completely serviced by them before I picked it up. Fuel filter bowl is crystal clear and the fuel filter is clean.

 

[Jim Goodman]

Could it be the stall guard?

I wonder about that too. Today I didn't work the machine but I did turn off the stall guard to see if the problem recurs.

 

[johnsayen]

I wonder about that too. Today I didn't work the machine but I did turn off the stall guard to see if the problem recurs.

If it is the stall guard, perhaps that’s how it’s supposed to act? Unsure.

 

[BigG]

Looking at a fuel filter does nothing. Replace it. Water messing up a filter will look brand new.

 

[kubotafreak]

How much do you weigh? Were you lifting off the seat, or leaning forward?

 

[Nicfin36]

How much do you weigh? Were you lifting off the seat, or leaning forward?

What I was going to suggest. Are you lifting off the seat activating the seat safety switch?

 

[Jchonline]

I bought it from a dealer and it was completely serviced by them before I picked it up. Fuel filter bowl is crystal clear and the fuel filter is clean.

Are you slightly getting out of the seat looking at where you are putting the forks and thereby activating the seat safety switch?

Second I would recommend is to turn the auto stall guard off and try that.

 

[Jim Goodman]

How much do you weigh? Were you lifting off the seat, or leaning forward?

I weigh 190, so it's not an issue of me being too light .

I definitely am leaning forward to see the forks when I'm creeping forward to slide the forks in between 2 units of lumber, but I'm not sure if I might be lifting off the seat or not. I'll intentionally do that and see if that might be what I was doing unknowingly. I bought this machine used, from a dealer this week, and I have not yet flipped the seat up to look at the safety switch. All that I have done with it this week is shuttle around some stacks of lumber. So, for example, I'll have a unit of lumber on the forks and I've pulled up to the spot where I want to put it down. I have the forks with the lumber 12" off the ground. I need to place the stickers on the ground so I can place the lumber on the stickers. I'll have tractor idling, treadle pedal in the neutral position, and I can get off the tractor to place the stickers and it continues to run. Lifting off the seat does not shut it down, so I'm wondering if the seat safety switch might have been jumped by the previous owner. Or, is it only if the machine is in motion that lifting off the seat will shut it down?

 

[Jim Goodman]

Are you slightly getting out of the seat looking at where you are putting the forks and thereby activating the seat safety switch?

Second I would recommend is to turn the auto stall guard off and try that.

Thank you. I'm definitely leaning forward but not sure if I'm lifting off the seat.....I'll intentionally do that and see if it recreates the situation. And I have now turned off the stall guard too.

 

[sheepfarmer]

I weigh 190, so it's not an issue of me being too light .

I definitely am leaning forward to see the forks when I'm creeping forward to slide the forks in between 2 units of lumber, but I'm not sure if I might be lifting off the seat or not. I'll intentionally do that and see if that might be what I was doing unknowingly. I bought this machine used, from a dealer this week, and I have not yet flipped the seat up to look at the safety switch. All that I have done with it this week is shuttle around some stacks of lumber. So, for example, I'll have a unit of lumber on the forks and I've pulled up to the spot where I want to put it down. I have the forks with the lumber 12" off the ground. I need to place the stickers on the ground so I can place the lumber on the stickers. I'll have tractor idling, treadle pedal in the neutral position, and I can get off the tractor to place the stickers and it continues to run. Lifting off the seat does not shut it down, so I'm wondering if the seat safety switch might have been jumped by the previous owner. Or, is it only if the machine is in motion that lifting off the seat will shut it down?

Lifting off the seat will only stall the tractor if you are in motion, so both the safety switch in the treadle pedal and the seat switch must be working correctly.

 

[Jchonline]

Lifting off the seat will only stall the tractor if you are in motion, so both the safety switch in the treadle pedal and the seat switch must be working correctly.

Well not in motion…but if you press the pedal and you are off the seat…even if you aren’t actually rolling yet. It will bog.

OP its a simple test..just be sure your butt is planted fully in the seat when you try lifting/moving forward. You can simulate this in a place that wont accidentally damage your shelves/stacking spot if you can’t see.

 

[Jim Goodman]

Well not in motion…but if you press the pedal and you are off the seat…even if you aren’t actually rolling yet. It will bog.

OP its a simple test..just be sure your butt is planted fully in the seat when you try lifting/moving forward. You can simulate this in a place that wont accidentally damage your shelves/stacking spot if you can’t see.

Great, thanks for that information. I'll try that test. The fact that lifting off the seat will kill the motor when you are standing still but trying to lift something......I think that may be what I was doing. I'll test it out. Thanks again.

 

[Jim Goodman]

Well not in motion…but if you press the pedal and you are off the seat…even if you aren’t actually rolling yet. It will bog.

OP its a simple test..just be sure your butt is planted fully in the seat when you try lifting/moving forward. You can simulate this in a place that wont accidentally damage your shelves/stacking spot if you can’t see.

You were exactly right.....I was lifting my butt slightly off the seat when I leaned forward and that triggered the safety switch. Thank you very much!

 

[Jchonline]

You were exactly right.....I was lifting my butt slightly off the seat when I leaned forward and that triggered the safety switch. Thank you very much!

You bet Jim, it has happened to all of us!

 

[jimr63]

You were exactly right.....I was lifting my butt slightly off the seat when I leaned forward and that triggered the safety switch. Thank you very much!

I removed the safety switch from bottom of the seat on my L47 and put a zip tie around it so it thinks I’m in the seat all the time. Never felt the need to do it on any of my other tractors but the seat switch on the L47 is way too sensitive.