425 Need help

[Central_PA_Chris]

Howdy all,

I have a PT425, 28 hours on it (mostly mowing) had it about 15 months, of which it's been in a shop for 6+ and in late fall/winter/early spring drydock for almost the entire other 9.

In addition to the problems which landed it in the shop, it seems to have lots of trouble with what I'd call minor hills and slopes, not wanting to climb, spinning one wheel (isn't this thing supposed to be 4 wheel drive?) and getting flummoxed by terrain that a honda accord would traverse with impunity.

I'd be very grateful if another 425 (or similar model) owner in PA would be willing to let me tow this thing to you to test drive to see if it performs as yours does or if when used by someone with experience it has a significant issue that I need to drag it back to Tazwell for. Drop me a PM or post if you are willing to lend a hand to one of the less lucky/successful/happy members of the Power Trac family. I'm in the central PA area, a bit outside of State College, so most of the state is in easy road trip range. I tend to get to the NE/Scranton area frequently, and occasionally down to the Pittsburgh region, so might be able to tie a test mission into a regular trip.

Thanks,
Chris

 

[SnowRidge]

I'm not in PA or otherwise close enough. However, I'm interested in your problem.

Do you have a situation where one wheel spins while the other wheel on the same side doesn't rotate?

If that is the case, the only things I can think of that would cause that is a hydraulic plumbing error or a wheel motor with a serious internal leak. The wheels should be plumbed in series on each side. The two sides are plumbed in parallel.

Normally, if a wheel loses traction, it won't spin any faster than its mate on the same side, since the fluid must pass through both wheel motors for either to rotate. Once in awhile, you may see a little extra slow motion speed up by the slipping wheel as fluid equalizes in the hoses, but it usually is less than one full revolution.

If a wheel motor were to go bad in a manner that allowed the fluid to bypass interally, you possibly could get a situation as you describe. I've not heard of anyone having that sort of failure, but it may be possible. In that case, the bad motor would essentially be along for the ride.

Why has the machine been in the shop, and who is doing the work on it?

 

[ernemats]

Chris I have a 422 with 1,320 hours on it over the past 8 years and also an older 1845 slope mower. I live about 2 hours away from you down toward Pittsburgh. If you want to stop by and try my 422 on my hills or bring your 425 you are more than welcome. I am about 15 miles west of Johnstown between New Florence and Ligonier.

 

[Central_PA_Chris]

Hey all,

A member about a half hour south of me with a 425 has offered to help, so I'm good to go at the moment. If I need more help, Bolivar is in my line of travel on a trip next week. Thanks for all the offers of help.

If I go up a slope, one that a 2-wheel drive car or truck can take (barely), the PT slows, I let off the treadle as machine slows, eventually nothing is spinning despite hearing load on the engine. If I press a bit more on the treadle sometimes ONE tire starts spinning, digging in but generally not propelling the machine forward, many times it gives a half spin and the machine stalls, but it's just one tire (in my recent round of testing it's been rear). I believe the other tires do have some drive power to them as I've seen the front spin as well.

I'll probably take a video camera to the side by side test to document.

Chris

 

[Central_PA_Chris]

As for the issue it's been in the shop for, I'm this guy....

http://www.tractorbynet.com/forums/power-trac/107255-bad-power-trac-experience.html

http://www.tractorbynet.com/forums/power-trac/114149-pointer-425-tbn-classifieds.html

The problem seemed to be solved by the air filter replacement, but I didn't get to mow much at the end of 07 (just one run on dryed out weed filled fields when it was very cold out).

Fired her up this spring and still have overheating issues after a short run of mowing. Gets so hot in there (after about 3-4 hours of mowing in cool spring weather) the engine stalls and the gas tank is bubbling like an overheated radiator from gas vapor flowing violently back into the tank from the carb and the air filter was again wet with oil. The next day I decided to do more trouble shooting (had a IR thermometer to get surface temps with) one of the mower blades got stuck on one of the kickback stops, I freed it but jammed again on next fire up. I decided I was frustrated and discontinued any testing as my busy work season was starting up and dropped it off at the shop, that was early May. Got it back last week, shop concluded poor design of muffler, restricted airflow over the engine makes it an intermittent use machine not designed or meant for mowing for more than a few hours at a clip before a few hour cool down/rest.

The sum of my experience leads me to believe I got a bad machine right from the start. Maybe bad engine, maybe, bad hydraulics, maybe both. I don't know because this is the only one I've ever driven/used. So now it's time to drive another/have someone experienced drive mine. If another performs as I think it should, then I call Terry and if they will help me after I've expressed my negative opinions here, I probably drive it the 8 hours to Tazwell and sit for a few days while it gets looked at or drop it off and have to make the trek twice.

I like a lot of things about this machine and really want to like it as a whole, but my overall experience has been horrible and I'm afraid that keeping it means more of these shenanigans for the life of the tractor. I'm more let down and disappointed than angry, but I should probably be that too.

Chris

P.S. I really don't like being a downer on these forums, this seems like it should be an incredible machine and y'all are a great helpful group of enthusiasts that I'd really like to join in welding up new attachments and enjoying the machine, but I can't use it for more than 4 hours before something (large or small) breaks and it's hard to maintain enthusiasm under those conditions.

EDIT: For example, yesterday I had it up at my dad's place to try it on some different hills. Still wasn't good, Dad said it had to have issues as no tractor should have the slope climbing issues this one does. Today I go to fire it up to get it off the trailer. Engine turns over but will not start. I'll try jumping it, but this is the last thing I need on this tractor, yet another problem. Maybe I just flooded it when starting, but it's never happened before.

 

[Central_PA_Chris]

Jumped it (started instantly and started sounded less anemic under jump voltage, so maybe new battery time), took it out to mow for an hour on low slope (2 to 4% grade). Can really feel the difference between uphill and downhill in speed you can mow, but in the hour didn't notice any heat related issues, it was also cold enough that after a brief rain shower I was almost shivering, so not a warm day.

In a little off kilter ditch area I got both left side tires to spin at the same speed, when the right spins it's just the rear. I may need to play with that some more to confirm that that is always the case, but maybe the front right wheel motor is bad and is putting a load on the system, especially when things are hot or is putting more of a load on the system than it should when worked (as in going up hill).

 

[Marks481]

I really don't like being a downer on these forums

Don't worry about it; that is what this forum is all about. If you have problems, bring them up and let everyone try to help. You have definitely been much more restrained and gentlemanly about your difficulties then I would be if my PT had all the problems you have had in such a short time.

re: overheating and bubbling gas tank. I think this is a combination of PT crummy muffler design and the location of the gas pump. The muffler and exhuast header tends to trap heat under the engine cowling (the top of my list to fix, ala Rivco's solution). The gas pump is right next to the muffler, so it probably gets way too hot.

The first solution step is to replace the cheap clear plastic gas line with some thick rubber tubing to keep the heat away from the fuel. At least one person here replaced the fuel pump with an electric pump. You could also simply relocate the mechanical fuel pump (as it is driven by a "pulse pipe" instead of a mechanical shaft).

 

[SnowRidge]

In a little off kilter ditch area I got both left side tires to spin at the same speed, when the right spins it's just the rear. I may need to play with that some more to confirm that that is always the case, but maybe the front right wheel motor is bad and is putting a load on the system, especially when things are hot or is putting more of a load on the system than it should when worked (as in going up hill).

Assuming the ground wasn't soupy wet, for one side to spin, you usually have to have something unloading those wheels, like the belly hanging up on a high spot, which is pretty unusual with a Power Trac.

The other thing to watch for is the joystick coming out of float position, which can unload the front wheels if there is any down pressure on the mower. Some owners have had a problem with their machines staying in float. There is at least one thread here on the subject.

It might be worthwhile to put the machine up on four jack stands to see if all the wheels turn at the same rate under various treadle positions. They should.

A floor jack and four short jack stands come in very handy if you own a Power Trac.

 

[BobRip]

As for the issue it's been in the shop for, I'm this guy....


Chris, when mowing on a hill, I find that I sometimes have to lift the mower a little to take the weight on of its wheels and transfer it to the PT. This give the PT better traction. Have you tried this?

 

[Phils]

Chris,

You didn't have the PT long before the fire IIRC. Could the Robin mechanic have screwed up a hydraulic part (pump or hose) or connected them incorrectly when reinstalling? We are all looking forward to hearing the verdict when you compare PTs with your nearby TBN member.

And as far as the hot engine, boiling fuel, stalling, running lean... it'll run lean when the fuel is boiling... which makes the engine run hotter ... which makes the fuel hotter... until the engine stops. Find the threads on adding a second cooling fan. My overheat and vaporlock problems are history. And it wasn't an expensive fix.

Before the fan I installed an electric pump but believe the cooling fan might've solved my problems without it. It mostly comes back to the lousy exhaust and muffler design.

Phil

 

[cqaigy2]

And my lean running problem was taken care of when i cleaned all the crap out of the fuel delivery system. Connector at bottom of fuel tank full of plastic glue stuff and all the way into the carb and fuel shut off solenoid.


And thank you tractorbynet for spell check

 

[MuncyBob]

While I have not had any vapor lock problems I can say that the bubbling in the fuel tank was reduced considerably when I took the poor man's(and lazy!) approach and simply lined the fuel line with aluminum foil. One day I'll replace the line and filter...but until then this seems to be a fix.

 

[cqaigy2]

While I have not had any vapor lock problems I can say that the bubbling in the fuel tank was reduced considerably when I took the poor man's(and lazy!) approach and simply lined the fuel line with aluminum foil. One day I'll replace the line and filter...but until then this seems to be a fix.

I did that for a while too, actually still doing it.

 

[Central_PA_Chris]

OK, couple answers. Play date for the tractors went well (thanks ahartman!). It was good meeting a local PT owner & his family & pets it was a fun time on a nice sunny, but cool day.

His 425 had the Kohlar (mine's the Robins) 25HP engine. I think his was a '03. His handled hills better than the newer, went nice and steady up a hill that mine (with mower on the front but PTO off) bogged down on. It was an incomplete test, only ran mine for 40 min or less and it was a cool day, so not up to the higher temps where the issues are more noticeable.

The other member also concluded that something was funny and not right about my PT. Basically the PT gets to a point where it stops going uphill, while the treadle is partly depressed, but the engine doesn't sound like it's under much load, it doesn't bog down, just sits there not going anywhere, press a but further on the treadle, and sometimes it starts going uphill again, sometimes it stalls (no stalls today).

The hydro fluid has to be going somewhere, why would the fluid bypass the wheels and maybe/sometimes start them spinning when treadle depressed more?

I did come away with a list of PT to do's, tops is check the towing/bypass valve to make sure it's fully closed. I/we concluded that that's probably not it as it doesn't slide downhill on big hills, but I'll give it a try.

I can replicate the lack of torque when loading the PT onto my trailer, I have a tilt bed, so it's a 3-4" lip to get onto the bed. If the PT is not in motion when at that lip it will sit there and when treadle is depressed not do a darn thing, no tire spinning, no engine bog down. I have to get a running leap to bounce up onto the bed. I'm totally ignorant about how the system really works, but it's kinda like a hydraulic overload bypass is opening up way too soon rather than giving the wheels torque to spin in lowest/first/barely depressed treadle position.

RE prior questions:
I have noticed it popping out of float occasionally, I greased it up and seems to be working again. The joystick base was a bit rusted when it came back from the shop and that's when it started doing that little shenanigan.

Yes, I have found that picking the mower up and eliminating that drag on the front can help get it moving when it's having issues with a slope.

Thanks for all the tips on the fuel issues, they should fix me up on that front.

I don't have a lot of time (or room in the shop) at the moment, but I guess this winter I'll log into a bunch of PT cooling projects. Just gotta figure out the wheel torque issue and maybe, just maybe, the old 425 will be worth keeping.

 

[SnowRidge]

Did you get a manual with the machine? It should have a hydraulic plumbing diagram. It's not the best diagram in the world, but it is usable. I would definitely verify that every hydraulic hose runs to the right place, especially since you had a shop working on the machine that wasn't familiar with PTs.

If the machine isn't going anywhere with the treadle depressed, you need to check and see if the control on the variable volume drive pump is moving in concert with the treadle. That's easy to do on the older hydroback/cable models like mine, but I don't know about the hydraulically operated control that yours has. The control rotates one direction when the right treadle is depressed and the other direction when the left treadle is depressed. The amount of rotation should be roughly equal for each direction.

If the pump control is moving appropriately, then it might be a bad pump, which wouldn't be good news. The pumps have to have the air bled out of them anytime the hydraulic circuit is disconnected. If that isn't done, they are susceptible to damage. Is there any chance that the shop that worked on the machine, disconnected the hydraulic lines or removed the hydraulic filter and didn't properly bleed the system?

If it is the pump, and it was bad from the get go, it might still be under warranty. Aside from the engine, it is the most expensive component on the machine. Somebody posted that one or more of the pumps have a two year warranty. That would be worth checking into.

If it hasn't already been done, change the hydraulic filter and bleed the system before you run the machine anymore. It might be bad or partially clogged.

 

[J_J]

Central PA Chris,

Have you ever put a hydraulic pressure gage on the system? A $15.00 hydraulic gage will tell you what is happening with the system. You can put a tee and quick disconnect in each of the circuits and analyze the situation. A hydraulic shop will charge you about $65.00 to look at the system. I would call Terry at PT and ask for the pressure readings that should be present in the different circuits. It sounds like you have a weak pump. Can you verify that the fwd/reverse lever on the pump is operating at it's full range. There should be enough torque in low range to operate some hills. Is your PT still under warranty?

 

[Central_PA_Chris]

I have to run to Pittsburg for 2 days and gotta flee out the door right now, but here's a quickie. I don't think it's the treadle as when it is going up a hill in slow/least depressed mode it will stop going up hill with no change in treadle pressing and just sit there w/treadle in same position.

The hydraulic system as a whole works well, always seems to be enough PTO power to run the mower can cut everything quite well. Ahartman said he thinks it cuts brush better than his (though could be blade sharpness differences).

It has been doing this same thing since I picked it up. I had difficulty getting it on my trailer in the PT parking lot in Tazwell, I wrote it off to my inexperience in use at the time. Machine is now +-15 months from purchase, 30.9 hours on it.

It will go up some hills, but many fewer when everything is hot.

I don't think the shop did any disconnection of hydraulics.

I'll give Terry a call when I get back from this quick trip. I can easilly video the trailer loading issue and mail/email that down to him to look at since that at least is easily replicable.

 

[SnowRidge]

There are three hydraulic systems on the machine, not one. Other than the mechanical coupling of the pumps and the common hydraulic reservoir, they are completely independent. The fact that the PTO works fine has no bearing on the wheel drive system, except when the combined load of the two systems exceeds the motor's available power output, in which case it bogs down. That isn't happening, so you can disregard the PTO system in this case. You need to look at the drive system and its controls.

Two of us have suggested that you verify that the treadle is moving the drive pump control properly. We made these suggestions for a reason. If nothing else, eliminate the easy stuff first. You don't want to tear into the drive system if there is air in the treadle control lines, or it is something else of that ilk. Air in any hydraulically operated control system will result in that system operating improperly. Temperature changes may exacerbate it. You need to check and eliminate the treadle system as the root cause of the problem, especially since you state that the engine doesn't seem to be under any particularly heavy load. Then move on to the expensive part, the pump.

 

[ldabe]

Snowridge,
You sound like you know exactly what your talking about, and say it with authority.
(You should be a "statesman", because the polititians do exactly the opposite.)

If it were me, I would heed Snowridge's advice.

 

[SnowRidge]

I just came across my PDF copy of the drive pump manual. Provided they are still using the same pump, which seems likely, the specs call for +/-15 degrees max rotation for the control shaft that is operated by the treadle.

The control shaft operates an internal swashplate that controls direction and flow of the pump's output. The manual states that the control shaft has no internal spring or other centering device, and that internal forces may move the control in either direction, therefore the control system must hold the swashplate control shaft at the desired angle.

I read that to say that a sloppy or loose treadle control could result in erratic operation.