Mowing pto problems
- Thread starter markkas
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woodlandfarms
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Mine was doing the same. It turned out it was a bearing in my mower spindle.
I checked the bearings wasn't them. It will bog down but if you back off the high grass it will spin back upto full speed. Seems like there is just a loss of power under a heavy load.
Thanks,
Mark
Marks481
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Maybe it is hydraulic oil temp? After 90 minutes, the ol is getting hot and losing viscosity, and reducing the amount of work that it can do.
is your hydraulic oil fan operating when your oil gets hot?
is your hydraulic oil fan operating when your oil gets hot?
cqaigy2
Super Member
pressure relief set too low?
Phils
Platinum Member
I'm agreeing with tmarks11. I experience this everytime I do long periods of stump grinding. As the oil heats up, the PTO loses power.
Phil
Phil
SpringHollow
Elite Member
I installed a thermometer into my tank lid. If I can remember, I will shoot the side of the hydraulic tank with an IR thermometer and compare it to the thermometer reading after bush hogging for a while.
Ken
Ken
woodlandfarms
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I mow a lot, like 20 + acres. I run an average of 5 hours a shift, and it takes me around 25 hours to complete (due to hills, trees, blah blah blah). I do not have a thermometer on my tank, just on my engine. But I have not run that hot. I do use a thermal measure on my tank from time to time. Once I get my mower back together I will take a measurement on a hot day. I don't think I am much over 190 and it usually holds there.
I am going to say again I think it is something else. Maybe dull blades? You may be more aware of it slowing down as you become more focused on mowing (getting back the inital startup rush?)
What JJ is going to say is this. Run your mower till you feel it bogging down. Then attach a dead headed pressure meter to the PTO circuit (disconnect your mower and attach a meter which is very simple to build and not too expensive). If you don't have 3000 PSI (like it is crazy low) then your eitehr have an issue with your pump or your by-pass (which is in the PTO circuit).
My bypass got clogged once with debris from a pipe that gave up the ghost.
If you have high pressure then you need to look to see if your mower motor is bypassing when it gets warm.
I still think it is the bearings. OR!!!! Or it could be your belt. I had an issue with my belt getting warm and slipping. I painted a whole bunch of marks on the belt and found I needed to tighten it a bit as it stretched when it got hot. I replaced the belt not to long after.
I am going to say again I think it is something else. Maybe dull blades? You may be more aware of it slowing down as you become more focused on mowing (getting back the inital startup rush?)
What JJ is going to say is this. Run your mower till you feel it bogging down. Then attach a dead headed pressure meter to the PTO circuit (disconnect your mower and attach a meter which is very simple to build and not too expensive). If you don't have 3000 PSI (like it is crazy low) then your eitehr have an issue with your pump or your by-pass (which is in the PTO circuit).
My bypass got clogged once with debris from a pipe that gave up the ghost.
If you have high pressure then you need to look to see if your mower motor is bypassing when it gets warm.
I still think it is the bearings. OR!!!! Or it could be your belt. I had an issue with my belt getting warm and slipping. I painted a whole bunch of marks on the belt and found I needed to tighten it a bit as it stretched when it got hot. I replaced the belt not to long after.
J_J
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I would think that is normal for the motor to lose efficiency as the fluid gets hot.
If all the parts in the motor are not made of the same material, some parts will expand more than others, and bypassing may occur.
The pump and motor may have some wear and not producing the GPM's and the power from the motor you think it should.
The pump will also get hot and lose some efficiency but will still try and pump a certain volume, and the motor will try and use the fluid to develop pressure and therefore work.
If you install a gage in the hyd circuit, you can see the pressure change as you operate the machine over time. You can also see the effects of the load on the motor and therefore on the pressure.
If you see the pressure up around the relief pressure, you know the motor is doing what it is supposed to.
If you go to stall mode, the excess pressure and flow will pass over the relief valve and the flow to the motor will decease.
Both my stump grinder and flail mower will do this if I overload them.
If all the parts in the motor are not made of the same material, some parts will expand more than others, and bypassing may occur.
The pump and motor may have some wear and not producing the GPM's and the power from the motor you think it should.
The pump will also get hot and lose some efficiency but will still try and pump a certain volume, and the motor will try and use the fluid to develop pressure and therefore work.
If you install a gage in the hyd circuit, you can see the pressure change as you operate the machine over time. You can also see the effects of the load on the motor and therefore on the pressure.
If you see the pressure up around the relief pressure, you know the motor is doing what it is supposed to.
If you go to stall mode, the excess pressure and flow will pass over the relief valve and the flow to the motor will decease.
Both my stump grinder and flail mower will do this if I overload them.
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