Kubota Power Loss

RiverCamper · Mar 31, 2009

I’m new to the forum but need some help…my Kubota 900 with a 150 hours will not run over 12 MPH after repair and service. What should I be trouble shooting? Here is the story… My daughter was driving the RTV with the dump bed lever in the down position. The hydraulic fluid melted the plastic hydraulic tank. Replaced the tank with a metal tank…no worky. Checked the hydraulic fluid no pump action. Pulled the hydraulic pump found the pump bearings housings cracked. Rebuilt the hydraulic pump, changed hydraulic fluid, flushed and changed transmission fluid and filters (found all metal parts of the hydr pmp bearing housing attached to magnetic plug when the transmission fluid was drained). The hydraulic dump works better than factory but the engine does not have the same power and runs no faster than 12 mph in H. It use to run18 to20 mph before the hydraulic pump was changed. Also changed fuel and air filters no change. The engine does not miss but “seems” to be running at lower RPM? with full pedal pressure. What should I trouble shoot...a fuel problem or a transmission problem? Thanks for the help. The RiverCamper.

TWO GUNS · Mar 31, 2009

Welcome to the forum River Camper !!!!! 

Sorry to hear about your problem. That fluid really got hot * hot * hot to melt that tank. 

Did you go back with OEM Kubota filters and Super UDT hydro fluids? When you say " found all metal parts of the hydro pump housingattached to the magnetic plug" , what kind of parts areyou talking about ? Are youtalking about metal shavings ? Did you run your engine hot ?What quality of fuel are you running ?

How much of this have you talked over with a Kubota mechanic ? Or your dealer ?

~~~~~~~~ let me think a little on this one !!!





~~~~~~~ two guns >>>>>>>>

bordercollie · Mar 31, 2009

Welcome River camper, Sorry to hear of your troubles. What year model do you have? I would go ahead and consider removing the spark arrestor. As members will attest to... they clog up and cause a lot of problems such as low power. On the hydraulics, I will leave that to other members. Good luck!! Bordercollie

TWO GUNS · Mar 31, 2009

Yes, I agree with Bordercollie, start with the arrestor >>>>>

two guns >>>>>>>>

Peanut · Mar 31, 2009

i don't know much about the motors or pumps but if it's not the arestor you think maybe that sinse you got it so hot as to melt the tank that maybe you fried a few o ring seals in the pump too and some oil is just bypassing??

muleman2 · Mar 31, 2009

Try raising the bed and with the motor off, check the pedal travel and see if there is slop in the linkage. If it got that hot cable may have stretched a little. See if the governor is moving . Good luck. Bill

Brian Bolger · Apr 1, 2009

Somewhere on this site I remember reading an owner had trouble with the Shift Assist being too tight and holding the hydraulic release open a tiny bit. Easy check to see if it is adjusted proplerly. Should have a little slack in the cable.

RiverCamper · Apr 1, 2009

Thanks for all your input, a lot of information. Will print out this thread, carry to the River Camp, grab a wrench and get to work. One other thing I did not mention, the melting of the hydr dump tank occurred the last week of hunting season. Looked at the situation and IMO the broken hydr dumpwas not related to the engine - drive train so…. we ran the RTV 900 several weeks while waiting on parts to replace the tank and rebuild the hydr dump pump with no change in the engine speed or transmission. It was not until the hydr pump and resevoir were repaired that the loss of power occurred. Makes no sence. <o

></o

>

Two Guns[/b], went back with OEM Kubota parts and fluids. Plan to drain and replace all, also plan to drain and replace fuel. Although my tractor runs fine on the same diesel source. The engine never ran hot. Anyway will start the process on Saturday morning and give you guys a shout once we solve the problem. 

Pleeze, if you think of other possibilities or ideas send them my way. -RiverCamper-

TWO GUNS · Apr 1, 2009

RIVERCAMPER,

CHECK YOUREMAIL >>>>>

two guns ~~~~~~~~

Kubota Kanook · Apr 1, 2009

RiverCamper.........

Your original problem of the dumper tank melting is not new. There are a couple of other episodes of this problem mentioned on other threads in this forum, but yours is the 1st that seems to identify the cause. If i read your description correctly [quote user="RiverCamper"]

 Here is the story… My daughter was driving the RTV with the dump bed lever in the down position. 
<div style="CLEAR: both"></div>

[/quote]

Was the lever stuck in the down position as apposed to the neutral thus causing the pump to continuously force the dump cylinder down and causing the fluid to overheat and melt the tank???????

The other incidents didn't seem to be able to isolate the cause of the leak. If so this is a valuable observation and something i will keep an eye on. THANKS

Sorry, don't have any additional suggestions for your current issue but look forward to your update.

Good luck......

solitude · Apr 2, 2009

My2 cents worth
Kinda sounds like pump is staying engaged all the time!
Not sure what up down ever is attaches too maybe something
got jammed in that valve.seems like if it worked allright with pump out somethin may be keeping it engaged now.

RiverCamper · Apr 2, 2009

Kanook, 

FYI and the rest of the forum, I can document the cause of the hydraulic tank meltdown. The hydraulic fluid over heated and melted the tank because the dump lever was in the down position, continually pumping the fluid. My young daughter loves to drive the RTV’s. She was hauling fire woodto the house and dumping while we were cutting-splitting. She used the dump level lock to hold the lever in the down[/b] position while she drove. She was concerned with all the wood would dump on the trail so she locked it down. After +/-20 minutes the tank/hose connection melted. <o

></o

>
<o

></o

>Again thanks for all the great tips. Will get-it-done. ---RiverCamper---

bczoom · Apr 2, 2009

[quote user="RiverCamper"]Rebuilt the hydraulic pump, changed hydraulic fluid,

The hydraulic dump works better than factory but the engine does not have the same power and runs no faster than 12 mph in H. It use to run18 to20 mph before the hydraulic pump was changed.

The engine does not miss but “seems” to be running at lower RPM? with full pedal pressure. 

What should I trouble shoot...a fuel problem or a transmission problem? Thanks for the help. The RiverCamper.
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[/quote]

RiverCamper,

From your symptoms, I think there may be an issue in the hyd pump for the dump bed.

The items mentioned by other members not related to the bed dump are true causes of power loss and should be heeded and checked but yours seems to tie directly to that pump.

Because this started right after rebuilding that pump, coupled with decreased RPM's and MPH's, it sounds like your engine is under a load that it shouldn't have. It "sounds" like it's constantly working to feed that pump. I don't have my RTV here in my office (as Mrs. Zoom yells at me when I bring the RTV into the house) to take a look on how to do it, but I'd disconnect that pump from being powered by the engine and then see how your RTV runs. If it's better, something's wrong in that pump.

I can't help with what's wrong with the pump as my knowledge of hydraulics is pretty poor.

Onfoot · Apr 2, 2009

BCZoom's thoughts echo my own thinking on the subject. But if the pump was constantly working, it seems like you would get the heating problem again. Mind you, as I recall from the beginning of this thread, you replaced the plastic hydraulic tank. So maybe it can now take the heat...

bordercollie · Apr 2, 2009

River camper, Please know that I know nothing about hydraulics but I seem to remember something my Dad said. He had a hydraulic business in La. in the 70's and 80's. It was something about slowing down/ increasing the flow of a pump by changing or turning around one of the inner components of the pump.He actually built steering systems for tow boats in S. La. He had a flow meter and could fix anything hydraulic. I plan to visit them this weekend and will see if he remembers anything about it although he has had several strokes and has Parkinsons as well. Good luck Bordercollie.

Kubota Kanook · Apr 2, 2009

I'm reading the install instructions for the "Bed Lift Kit" and which involves the pump,tank valve etc. The instructions specifically state

"NOTE:Be careful NOT to contact HST linkage, damper or others."

This note is inserted in the instructions between steps 5 (mounting the valve assy) and step 6 (installing the the tank)

Kubota Kanook · Apr 2, 2009

[quote user="Kubota Kanook"]

I'm reading the install instructions for the "Bed Lift Kit" and which involves the pump,tank valve etc. The instructions specifically state

"NOTE:Be careful NOT to contact HST linkage, damper or others."

This note is inserted in the instructions between steps 5 (mounting the valve assy) and step 6 (installing the the tank)
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[/quote]

In looking at my unit I believe the note refers to the routing of the return hose to the tank. I can see how it could interfere with the HST linkage. Also i took mine for a spin and engaging the dump lever while driving presents a noticable load on the engine. If your pump is always engaged, it will affect your ground speed.

Looking forward to your eventual fix.

Peanut · Apr 2, 2009

the job i was doin when i got hurt was building hydralic offshore cranes and i would watch and help the mechanics and one thing i did learn was when you tinker with the wrong screw or turn one even a half turn the wrong way it will have drastic affects on the performance of the machine. workin with hydraulics is worse than setting an old carberator now if you know what your doing then you got it made but if you don't then your really up the creek. do you have a shop manual?? thats what you really need it will tell you what all the setting should be at.

Kubota Kanook · Apr 3, 2009

If your problem is being caused because the dump pump is under load in the neutral position you may also want to check the following. While working on the installation of my newly acquired bLIZZARD plow attachement , I had to remove the side cover (battery side) that exposes the linkage for the dump operating lever. The lock nut for the lever end cable linkage was very loose allowing the cable to slip about 1/2inch, thus the lever in the neutral position did not necessarily indicate the other end at the valve was in the appropriate position.

May not have anything to do with your problem, but thought I'd pass it on.

bordercollie · Apr 19, 2009

River camper, Does your pedal go all the way to the floor ? Check your speed control cable. it may have gotten moved slightly while doing repair on the pump. This info is on page 2-s13 of the shop manual if your dealer will zerox it for you. One thing it says is not to pull the accelerator wire too much when adjusting...Bordercollie

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