Kubota B8200 HST power problem

[jandpp]

My Kubota is a 3 cylinder diesel with hydrostatic transmission. When the throttle is any position including full on, the engine runs smoothly. The tractor operates well in low gear or at low drive speeds. However, when in middle range selector, the engine really bogs down when the forward pedal is fully depressed. The RPMs go down significantly and it almost stalls out. It runs fine at or below 3/4 full speed. The loader, 3 point, and PTO run fine.

I thought this was a fuel problem and changed fuel filter, cleaned fuel bowl, bled injector lines, and replaced air filter. No luck. The hydro fluid and filter were changed last Nov. Probably 10-20 hrs of use since then. Changed oil and filter too recently.

A basic question is if the engine seems to run fine at full throttle but loses power under drive load is this an engine problem or a hydraulic problem? Any ideas on what to try next?

 

[jonsstihl]

just a suggestion but is your parking brake on?

 

[jandpp]

just a suggestion but is your parking brake on?

No, good idea though.

I just talked to a local mechanic knowledgable about my particular tractor. I'm a relatively new owner just having purchased it last fall. The labels are missing so I'm not fully versed in operating it. First it appears that I am running in high gear rather than medium. Secondly, there is box under the dash with a lever. I was told that that was a FWD differential lock lever. But I've found on parts diagrams that it appears to be called a speed selector. This could be a lever that is giving my 2 speeds per gear. Thus I coud be running in high gear with high selector. My tractor has substantial (not sure how much) wheel weights so maybe that it too much load at this high speed.

Summary is that this could be expected behavior. Does this sound right? Am I identifying the box and lever under the dash correctly as a gear speed selector? It is a 1989 B8200 HST.

thanks,
jim

 

[dex3361]

Have you changed the HST fluid and filter as well as the suction screen(some have some dont). If there is a restriction in the HST fluid floe it will rob it of power and act as you described.

 

[RobertN]

I had a B8200HST-D for 12 years; it was a great tractor.

If you are sitting on the tractor:
- under your right leg is the range lever. It has a "U" pattern, for low-mid-high range. Low is down and to the left, Mid is up, and in the middle, High is down and to the right.
- at the botom of the dash is a mechanical cruise control
- behind your left foot is the differential lock "pedal"

It sounds, like you are going from Low range to High range. These tractors are big and heavy enough, that 19hp is not enough HP to really pull high range. I would only put it in high range to go downhill with a tailwind.

There is no "two speeds per gear" on this tractor. There is only low-mid-high; everything else is dependant on pressing the HST pedal forward or back.

Also, remember that if the tractor lugs, you want to ease up on the HST pedal, not push harder. HST is counter-intuitive in this regard.

FYI, there is no FWD diff lock; the diff lock only locks the rear differential(at least on a B8200)

Manuals are still available for that tractor; owners manul is ~$16 and is worth picking up.

You need to remove and clean the HST strainer when you change the HST fluid and filter. It is hard to describe without a diagram, but it is in one of the banjo fittings where the hydro pipe goes in to the tranny, below the right floorboard.

 

[dex3361]

Try here for a free parts manual for the tractor it is listed and its a PDF file and great to have for any machine.
B8200HST PDF

 

[RoyJackson]

I had a B8200HST-D for 12 years; it was a great tractor.

Excellent and informative post, Robert!
My compliments!

 

[jandpp]

This is very helpful advice. Thanks!

- at the botom of the dash is a mechanical cruise control
- behind your left foot is the differential lock "pedal"

There is no "two speeds per gear" on this tractor. There is only low-mid-high; everything else is dependant on pressing the HST pedal forward or back.

FYI, there is no FWD diff lock; the diff lock only locks the rear differential(at least on a B8200)

That explains what that lever is. I followed your advise and it appears that it is indeed cruise control.

Manuals are still available for that tractor; owners manul is ~$16 and is worth picking up.

I got a manual with the tractor but it's for the B8200 not B8200HST. So several of the levers are different, including the range selector and it doesn't mention the cruise control. I should buy a manual that matches my tractor but I haven't been able to find that particular one online. I do have parts manual and the Kubota shop manual for the tractor without engine.

You need to remove and clean the HST strainer when you change the HST fluid and filter. It is hard to describe without a diagram, but it is in one of the banjo fittings where the hydro pipe goes in to the tranny, below the right floorboard.

Yep. Did that when I replaced fluid and filter last fall.

So it appears that my tractor is running as expected. Again, I appreciate all the feedback.

 

[RobertN]

It appears you have the same manuals I had. I never did find a HST version of the manual.

It is a great tractor. I "upgraded to a 40hp tractor; wish I could have afforded to keep the B8200 too. I had added my own TnT to it.

Nice thing too, I was able to get all the filters ect from NAPA, 10 minutes away. Local Kubota was great, but was across Sacramento from me.

Kinda jealous I like my current tractor, but had a lot of hours driving that B8200

I got a manual with the tractor but it's for the B8200 not B8200HST. So several of the levers are different, including the range selector and it doesn't mention the cruise control. I should buy a manual that matches my tractor but I haven't been able to find that particular one online. I do have parts manual and the Kubota shop manual for the tractor without engine.

 

[Rich7]

I have the same problem with my B8200 . Loss of power, going to try changing out the fuel booster pump ,does not appear to be pumping much when cranking over . Will let you know if it solves the problem