B7500 HSD bogging down & overheating

[snowman]

My B7500 HSD was running a little hotter than normal this summer; not boiling over like yours though, and I haven't experienced any bogging down.

In line with what others have suggested here:

(a) check the coolant level (mine was down a little)
(b) pull off the outside grill and clean it thoroughly. The grass and dust that had built up between the grill and the
screen was helping to make it run hot, even though I always
kept the screen itself clean.
(c) make sure the radiator itself doesn't have debris up against the fins. The screen only catches some of the debris. I always have to clean the radiator itself - I just use a small stick and gently knock the stuff off with that.
(d) With the engine running, make sure that the fan is moving; that you don't have a broken belt.

Do you have the same problem in hi and lo gear and at any rpm? If so, it may be as others have suggested - something inside that may have broken.

Good luck

 

[enonhall]

</font><font color="blue" class="small">( Do you have the same problem in hi and lo gear and at any rpm? )</font>

Yes, I have the same problem in both hi and lo gear. I have not tested different rpm.

I have a number of things to try/test tomorrow...but I am really suspecting the mower more than the tractor right now. I'll post an update of what I find out. Thanks for everybody's good advice!

 

[kubmech]

Check for dragging brakes. should have about an inch of free play on the brake pedals.....If the 3ph goes up and down O.K. then I don't think it's a problem with hyd's stuck in relief.

 

[enonhall]

Well, I think I have tried everything in my means and it's time to call the dealer to come pick it up for service.

I blew out the radiator...there was some crud in there, but it wasn't caked by any means.
Air filter was clean.
Fluid levels all fine.
I checked the gearbox oil on the mower...fine.
I tightened the mower belt a little more.

None of this made any difference. As soon as the mower hit any grass that was even slightly tall or thick, the engine would bog down, RPMs would drop, and black smoke would emit from the engine. This would then cause the engine temp to rise.

I raised the deck by 1-1/2" and it was better, but still obviously not right.

It doesn't seem to be the thermostat since the motor temp drops rapidly as soon as I stop mowing.

What a pain in the butt! It was running like a dream just two weeks ago!

Again, thanks for everybody's input.

Bill

 

[Warwagon]

Bill,

Keep us informed on what the cause of the overheating is, it should be interesting. I was brushogging the other day and the temperature gauge was a little on the warm side, then I got into some heavy stuff and next time I looked down my tractor was way over-heated, it turns out the screen in front of the radiator was clogged. I cleaned it off and temp came back to normal. You can bet I will keep an eye on this from now on.
Good Luck, Kevin

 

[Egon]

Dealer time.

Slowzuki may be on the right track.

Just for interest will it do the same if you try to pull a heavy load like say hooking up to a tree and letting the tires spin very slowly? Hook low.

Egon

 

[theboman]

I guess you've blown out the grill and the screen in front of the radiator.

 

[enonhall]

</font><font color="blue" class="small">( I guess you've blown out the grill and the screen in front of the radiator. )</font>

Yup, they're clean.

 

[enonhall]

Here's an update:

Last week I had the Kubota dealer nearest me pick it up for service. I just got a call from the mechanic this morning saying that there is a transmission problem..."It's causing the mower to spin too fast." (That sounds a little weird given my symptoms...but what do I know.)

Then he told me that Kubota wants all warranty work to be performed by the dealer who sold the tractor...which for me is another dealer 80 miles away. Geez, if I had known that, I woulda called them in the first place! So I've called dealer #2 to come pick it up from dealer #1.

And I've called somebody to come cut my knee-deep grass.

Progress?

Bill /forums/images/graemlins/tongue.gif

 

[hwew]

I just read your problem with your b7500.
I have one also and it is a great tractor.
I noticed you are running a rear mower and a Kubota dealer said the mower is running too fast and is bogging down.
The b7500 has a two speed PTO.
It can run 540 RPM or 960 RPM.
It is in the owners manual how to operate it.
When you engage the rear pto for 540 RPM the lever should be moved toward the back of the tractor.
When you want to engage the rear pto for 960 RPM the lever should be moved toward the front of the tractor.
Note! when running the mid pto the rear pto will run at 960 rpm at the same time. The mid and rear pto share the same gear cluster. So make sure you do not have a rear attachment hooked up that runs on the rear pto because both will run and chances will be that the rear attachment is only rated to 540 RPM.

 

[enonhall]

Hi Henry -

Yes, I always operate the tractor in the 540 RPM (rear) position. Have never even moved that lever forward. Like I posted, what the mechanic said really isn't making sense to me.

Bill

 

[enonhall]

I heard back from the dealer today (dealer #2). They said nothing was wrong with the transmission (no surprise), but that they surely saw what was going on and, at first, couldn't figure out why it was happening. "It just didn't have any power."

Then they changed my brand new high lift blades out with standard blades and say that it was like adding 10HP. So they're now pointing the finger at the blades that dealer #1 recommended that I get after asking me if I have tall or thick grass. (Well, YEAH...it's been raining non-stop this summer!)

Dealer #2 went on about these blades creating a high vacuum or something. And also said that I should be using the standard or low lift blades anyway because I have sandy soil which tears up the blades. (The original blades lasted 100 hours.)

Does any of this make sense to anybody? They swear it's running great now and they can't make it overheat or bog down.

Bill

 

[jbcat2]

Does not sound right to me. The only time I had a temp problem was when my grill was filled with grass. (I was brush hogging w/ a 7500) If thats their official opinion, dont let them leave your house until after you cut your tall grass without any problems...I dont buy it.

 

[enonhall]

Well, it looks like "case closed" as regards to my overheating/power loss problem.

The tractor is running great and all they did was remove the brand new "high lift" blades, and replace them with standard blades. They say that the 21HP Kubota just couldn't handle the suction created by the high-lift blades. He also suggested that I really should be using low-suction blades because of my sandy soil...that they will last longer.

So this may be something new for folks to consider if they are experiencing severe overheating problems...and if they have recently changed their mower deck blades.

 

[JFight]

I know this is a old thread, but I really need this ... I have the same problem with my Kubota 2910B ... I'm very happy to hear that blades ( in this case ) were causing this issue, much cheaper than what it might / could have beenb... I hope that is all it is on mine !!! ... Thank you for updating and thanks to everyone for their suggestions and comments.