Mowing Finish Mower Not Working

[tlb]

I used my finish mower yesterday and at first it work fine. I turned the PTO off to move from the back yard to the front yard. When I turned the PTO switch on again, the I could hear the PT425 engine under load but the mower blades did not spin. I turned the PTO switch on and off several times but the mower blades failed to spin. I turned off the PTO and spun the blades by hand and everything was free and loose. I switched the mower out with a tiller and everything worked fine when I switched on the PTO.

Does anyone have any idea why the mower (hydraulic motor) is not turning?

-tim

 

[ldabe]

Not sure about yours, but mine has a belt under an enclosed guard.
By chance could it be the belt that turns the blades has broke?

 

[DHS]

Tim,

I had a similar problem two years ago with my PTO solenoid. I believe the ignition switch would heat up and dropped the voltage to the PTO solenoid. When the switch got hot the lower voltage partially opened the solenoid. I bought a new solenoid from PT but that was not the problem. Rather than replace the switch, I installed a wire with a fuse from the battery post on the starter to the PTO switch. No more PTO solenoid problems.

Try the PTO switch after the tractor cools for an hour of two. If it works it may be the voltage drop through the switch.

Keep us informed. This problem has several possible causes.

Dale

 

[BobRip]

Tim,

I had a similar problem two years ago with my PTO solenoid. I believe the ignition switch would heat up and dropped the voltage to the PTO solenoid. Rather than replace the switch, I installed a wire with a fuse from the battery post on the starter to the PTO switch. No more PTO solenoid problems.

Keep us informed. This problem has several possible causes.

Dale

Does the battery run down if you leave the PTO switch on after you shut off the engine?

 

[DHS]

Bob,

I assume it would. But, I have never left it on to find out. I left the wire connections to the ignition switch so if the PTO switch is on the motor will not start. That interlock remains inplace. But you are correct, if you turned on the PTO switch when the motor is off it will energize the solenoid.

Next time I order filters from Jacks small engines I plan to order a replacement switch.

Dale

 

[Bob999]

When I turned the PTO switch on again, the I could hear the PT425 engine under load but the mower blades did not spin. I turned off the PTO and spun the blades by hand and everything was free and loose. I switched the mower out with a tiller and everything worked fine when I switched on the PTO.

Does anyone have any idea why the mower (hydraulic motor) is not turning?

-tim

Because the engine loads when the PTO switch is turned on I believe that the PTO solenoid is working. The PTO pump is pumping all the time and the PTO switch simply reroutes the fluid from a bypass circuit to the quick connects on the front of the tractor. If nothing is connected to the quick connects or there is a blockage in a circuit attached to the PTO quick connects then the engine will load.

The fact that the tiller works but the mower does not, and because the mower blades turn freely, it suggests there is a problem with the motor on the mower or hydraulic lines on the mower.

 

[BobRip]

Have you checked the belts yet? An unloaded hydraulic motor would put some load on the engine.

 

[duane]

Check your charging system rectifier. (I presume your hydraulic cooler fan was running.) If your rectifier is not converting the flywheel coil AC to DC voltage, the hydraulic fan pulls down the battery such that voltage is insufficient to completely stroke the PTO solenoid valve. It strokes halfway and loads up the engine.

 

[tracdoc]

Hi Tim,

We're anxiously waiting to learn what the problem might be with your PTO solenoid and/or mower motor. Have you had an opportunity yet to do any more diagnostics?

Thanks for keeping us posted.

 

[tlb]

Sorry guys, but I have not had time to look at it yet. Since the PTO works fine with the tiller atttached, I am confident it is either in the mower hydraulic lines or mower hydraulic motor. Not knowing squat about hydraulic motors, I was hoping someone had run into this and knew the answer.

The blades turn freely and easily by hand. The belt (around 3 pulleys and the hydraulic motor shaft) turns easily. The hydraulic motor shaft spins freely by hand. So what's left that could cause it to not work?

Is there another test I could do to narrow down the problem? Are there debris screens or filters inside the motor or hydraulic lines? Any help is appreciated.
-Tim

 

[DHS]

Tim,

Have you tried the mower again since you used the tiller? The tiller may have worked because the PT and ignition switch cooled since the mower was used. Or, perhaps the hydraulic quick connects were not completely connected.

Before you fix something try the mower again. Make sure the hydraulic connections are fully seated. Let us know what happens.

Thanks

Dale

 

[MossRoad]

I used my finish mower yesterday and at first it work fine. I turned the PTO off to move from the back yard to the front yard. When I turned the PTO switch on again, the I could hear the PT425 engine under load but the mower blades did not spin. I turned the PTO switch on and off several times but the mower blades failed to spin. I turned off the PTO and spun the blades by hand and everything was free and loose. I switched the mower out with a tiller and everything worked fine when I switched on the PTO.

Does anyone have any idea why the mower (hydraulic motor) is not turning?

-tim

Some times I will have the machine at high throttle with the mower deck attached, and when I turn on the PTO switch, the hoses charge(you can see them move) but nothing happens. I turn off the PTO switch, throttle down to about 1/4 throttle and flip the PTO switch again. The hoses charge, the blades start turning, I let it spin for 5 or 10 seconds, then go to full throttle and mow. Give that a try next time you get a chance.

 

[Phils]

The next place I'd look is at the hydraulic connectors. I'm assuming you've connected/reconnected them a few times with the problem persisting. Could the check valve in one of them be malfunctioning? Other than a defective hose I can't think of what else it could be. I have seen hoses that've developed inside 'bubbles' that eventually formed little 'flaps' that restricted flow, but that was on OLD hoses and I wouldn't think it could be your problem. Easy enough to check: remove the hose from the motor, take off the quick disconnect and blow through it.

Phil

 

[ClintBlake]

Some times I will have the machine at high throttle with the mower deck attached, and when I turn on the PTO switch, the hoses charge(you can see them move) but nothing happens. I turn off the PTO switch, throttle down to about 1/4 throttle and flip the PTO switch again. The hoses charge, the blades start turning, I let it spin for 5 or 10 seconds, then go to full throttle and mow. Give that a try next time you get a chance.

When I picked up my PT in 99, they told me not to engage the PTO unless the engine was at an idle.

 

[J_J]

Sorry guys, but I have not had time to look at it yet. Since the PTO works fine with the tiller attached, I am confident it is either in the mower hydraulic lines or mower hydraulic motor. Not knowing squat about hydraulic motors, I was hoping someone had run into this and knew the answer.

The blades turn freely and easily by hand. The belt (around 3 pulleys and the hydraulic motor shaft) turns easily. The hydraulic motor shaft spins freely by hand. So what's left that could cause it to not work?

Is there another test I could do to narrow down the problem? Are there debris screens or filters inside the motor or hydraulic lines? Any help is appreciated.
-Tim

You did say that all the other implements work with the PTO.
When you activate the PTO switch, does the engine slow down, or do you hear the PTO relief valve operating. If you have the hoses connected correctly, and you flip the PTO switch on, you should get fluid flow through the PTO valve and lines to the hyd motor. You said the hyd motor turned freely, did you separate it from the spindle. I believe there is a coupler between the hyd motor and the spindle. If every thing checks out, it would seem that you have a blown hyd motor. Can you see if the hyd motor and spindle are turning at the same time, if not, the coupler is bad, The shaft key could be gone also. When you turn the blades by hand, is there rotation all the way back to the hydraulic motor?. If so, the motor is shot, that is assuming that you have hydraulic pressure out to the hyd motor. A pressure gage is worth every penny that you pay for it.

There is one other test I can think of. Without the hydraulic lines connected to anything, turn the blades by hand. They should be hard to turn with a good hydraulic motor. A good hydraulic motor, will try and act like a pump making it hard to turn unless something is broken. If the motor turns freely in this situation, take it to a hydraulic shop for testing, by now, you should already know the answer. Hydraulics are simple, When you pump fluid, that fluid is going somewhere, unless that pump is bad, which was the case in my situation. Pump had a lot of wear. With one of the tires off the ground, and you try to turn the tire by hand, it will be hard to turn. A good hydraulic motor will have lots of resistance.

 

[MossRoad]

When I picked up my PT in 99, they told me not to engage the PTO unless the engine was at an idle.

That's what I get for going mail order!

I have found that almost everyone that picks up their unit from the factory brings back a tip that I could have used. That is one of the pitfalls of not taking the factory training and the lack of documentation... fortunately, I was able to figure most things out and what I couldn't, you folks have helped me with.

 

[tlb]

Well, I tried the mower today and it worked fine. I engaged the PTO while the engine was idling then ran up the RPMs. So the conclusions are 1) either crude was stuck in the line and changing implements got rid of it, 2) the "hot" solenoid theory, or 3) "must engage PTO at low RPM" theory. The jury is still out to lunch!
-Tim

 

[Bob999]

Well, I tried the mower today and it worked fine. I engaged the PTO while the engine was idling then ran up the RPMs. So the conclusions are 1) either crude was stuck in the line and changing implements got rid of it, 2) the "hot" solenoid theory, or 3) "must engage PTO at low RPM" theory. The jury is still out to lunch!
-Tim

I suspect it was a solenoid problem--probably that the solenoid failed to pull in all the way.

 

[MossRoad]

Well, I tried the mower today and it worked fine. I engaged the PTO while the engine was idling then ran up the RPMs. So the conclusions are 1) either crude was stuck in the line and changing implements got rid of it, 2) the "hot" solenoid theory, or 3) "must engage PTO at low RPM" theory. The jury is still out to lunch!
-Tim

Great! Hopefully it will never happen again.