Bush Hog FINISHING MOWER uneven mowing

[allenport]

I am a new member and a woman. Please bear that in mind if my questions sound uneducated. I started using our 7 foot finishing mower in 2020 when my husband died. I have a part time helper, but he isn't really knowledgeable on farm machinery eithe r. Each year I have the tractor serviced by Kubota and they were the ones that hooked up the mower for me.

What is happening is that the place where the wheels contact the ground is cutting extremely low, almost making like a rut. You can see the wide patch between them that is higher. I do know the wheels press down the grass, but that isn't what is causing this. I also notice the rear discharge is coming more on left and right rather than evenly across the deck. That could be due to the cutting lower on the outside.

We have played around with the adjusting the spacers and that hasn't solved the problem. Before I call in the expensive Kubota service person, I'd like to see if any of you experienced people have any idea what is causing this?

I do mow a lot of uneven terrain, so I expect that to look uneven. But even on a flat path, I can see the vast difference.

Most recently in checking the spacers, I noticed that the front wheels weren't the same as the back. According to the manual, they should all be the same. We now have them the same and that seems to have made the problem worse.

Any suggestions would be appreciated. I can get photos if that helps.

 

[riptides]

First, welcome to TBN.

Photos are always good.

In your particular case, the type (model number, name brand) of finishing mower can help us out. I am sure someone will jump right in after that and tell you all about adjusting. That would be either the tractor attach points or the mower deck itself.

Again, welcome.

 

[chim]

Welcome aboard! Pictures are always helpful.

 

[K5lwq]

Welcome. Pictures for sure and pictures of the uneven cut would help too.

 

[RjCorazza]

Yes, pictures. Also raise the deck up and get some shots of the blades. 3 point finish mowers are easy to adjust assuming there is no geometry type damage to the wheels, yokes, or brackets. I suspect a blade may be out of whack.

 

[Jerry/MT]

I am a new member and a woman. Please bear that in mind if my questions sound uneducated. I started using our 7 foot finishing mower in 2020 when my husband died. I have a part time helper, but he isn't really knowledgeable on farm machinery eithe r. Each year I have the tractor serviced by Kubota and they were the ones that hooked up the mower for me.

What is happening is that the place where the wheels contact the ground is cutting extremely low, almost making like a rut. You can see the wide patch between them that is higher. I do know the wheels press down the grass, but that isn't what is causing this. I also notice the rear discharge is coming more on left and right rather than evenly across the deck. That could be due to the cutting lower on the outside.

We have played around with the adjusting the spacers and that hasn't solved the problem. Before I call in the expensive Kubota service person, I'd like to see if any of you experienced people have any idea what is causing this?

I do mow a lot of uneven terrain, so I expect that to look uneven. But even on a flat path, I can see the vast difference.

Most recently in checking the spacers, I noticed that the front wheels weren't the same as the back. According to the manual, they should all be the same. We now have them the same and that seems to have made the problem worse.

Any suggestions would be appreciated. I can get photos if that helps.

Without pictures and the model mower, it's hard to specifically diagnose your problem but I'm sure it is just getting the mower and the 3 point hitch adjusted properly.
If you have a flat spot of concrete, the general rule is to level the mower fore and aft and side to side. You can use a small spirit level to do this. Alternately you can measure the height of the mower at all four corners with a tape measure. I'm assuming nothing is bent on the mower frame. If you have or can get the mower's operator's manual, that would be your best bet to find out how to do this.

 

[old and tired]

Photos would help... I'm guessing that one of the blades hit something and is bent. Which could push more air to the other side while it's cutting lower...

Lift the mower up with the 3 point hitch and get a photo of the blades underneath....

 

[groundcover]

Pic is worth a thousand posts!
Also a location in your profile, someone nearby would probably swing by and give you a hand.

 

[Have tractor did travel]

Allenport - first - raise the deck and be sure the deck is clean underneath. Caked on grass (usually from mowing when dew still on the ground) can cause uneven cutting. A 2" stiff putty knife is good for removing caked grass.
I'm going to disagree with JerryM/T and the owner's manual - you do not want the deck even. You want the deck lower in the front and higher in the rear. In that manner, the blades cut the grass just one time. Minimum 1/4" difference.
Be sure your blades are sharp. If you're not sure they are sharp enough, look at the grass blade stem. If the ends are shredded and the next day they've turned tan, the blades are not sharp enough
If you have cool weather grass and are going for a good looking lawn, cut grass to 4". Do not cut more than 1/3 of the blade length at one time. That means you cut the grass at 6", and likely means you cut every 4 days during growing season. Over time, the healthy grass will push the weeds out of your lawn.
Post again after you've checked the underside of the deck for clogs of grass.

 

[Smokeydog]

Pictures and little more info helpful.

Agree proper adjustment of the deck is important. I keep the the front about 1/2” lower than the back.

On the Woods rd7200 had the left blade spindle pulley shear the two 1/4” clamp bolts that let the blade not spin under load.

We mow rough ground too. Had trouble with two brands of finish mowers bending the caster gauge wheels spindles. Causing the wheels to drag. Sharp turning 4wd tractor back and forth is hard on spindles. Finally figured out a fix with trailer spindles.

Good luck.

 

[allenport]

Thanks all for your help so far. As soon as the sun comes out, I'll start taking some photos.

I do have a response to some questions raised so far.

I'm in Ringoes, New Jersey in an agricultural district. There are probably lots of farmers that could help but everyone (as you probably know) is overloaded with their own work. Actually one of them farms some of my property.

The mower is a Bush Hog brand HDTH-8. I also have a pdf of the owners manual. The section on setting the mower states "Repeat these steps for all caster wheels making sure all are adjusted to the same height".

While googling for help, I also found an article (general on finishing mowers) that states the following on Deck Angle:

"With any rotary mower, it is desirable to set the front slightly lower so the blade cuts at the front and the rear of the blade does not recut the grass or drag on the grass. The slight angle should be designed into your finishing mower so that all you have to do is set the front and rear wheels to the same position to achieve the correct nose down cut" .

In any case, the mower was cutting unevenly before we made all wheels the same height. Actually, it was cutting lower on one side too.

I wouldn't be surprised if something is bent. I'm not even sure when this thing was purchased. It may have been purchased used. I know it didn't get much use here because I always had my riding ring harrow hooked to the tractor and it was a pain to keep changing the implements.

I did just this morning go out and raise the deck to see if there was grass clogged and there was not. My handyman does clean that routinely. I think he also sharpens the blades or the kubota guy does.

The other thing that could be a problem is that this mower is probably too wide for the tractor. When we first started using it, my handyman couldn't operate it because it was swaying and coming on the tractor. It's really probably too wide for the tractor which is a Kubota L3400. That's why I got the Kubota guy out and he put it on. It has not been removed since.

 

[riptides]

Thanks all for your help so far. As soon as the sun comes out, I'll start taking some photos.

I do have a response to some questions raised so far.

I'm in Ringoes, New Jersey in an agricultural district. There are probably lots of farmers that could help but everyone (as you probably know) is overloaded with their own work. Actually one of them farms some of my property.

The mower is a Bush Hog brand HDTH-8. I also have a pdf of the owners manual. The section on setting the mower states "Repeat these steps for all caster wheels making sure all are adjusted to the same height".

While googling for help, I also found an article (general on finishing mowers) that states the following on Deck Angle:

"With any rotary mower, it is desirable to set the front slightly lower so the blade cuts at the front and the rear of the blade does not recut the grass or drag on the grass. The slight angle should be designed into your finishing mower so that all you have to do is set the front and rear wheels to the same position to achieve the correct nose down cut" .

In any case, the mower was cutting unevenly before we made all wheels the same height. Actually, it was cutting lower on one side too.

I wouldn't be surprised if something is bent. I'm not even sure when this thing was purchased. It may have been purchased used. I know it didn't get much use here because I always had my riding ring harrow hooked to the tractor and it was a pain to keep changing the implements.

I did just this morning go out and raise the deck to see if there was grass clogged and there was not. My handyman does clean that routinely. I think he also sharpens the blades or the kubota guy does.

The other thing that could be a problem is that this mower is probably too wide for the tractor. When we first started using it, my handyman couldn't operate it because it was swaying and coming on the tractor. It's really probably too wide for the tractor which is a Kubota L3400. That's why I got the Kubota guy out and he put it on. It has not been removed since.

Good info.

To me, without seeing the pictures, it really sounds like the mower attached to the tractor (lift arms) are out of alignment. There should be a lift arm on the tractor that is adjustable. Turning it may require some effort. If you are on a level surface, and eyeballing which side the uneven cut is on, with the mower deck down, may reveal that adjustment issue.

You mentioned swaying. That is also the mower attaching to the tractor. There should be further adjustments on the hitch swings to tighter that up. These are "arms" that the mower is attached to. Lift the mower up, and attempt to rock it back from side to side. There should be just enough motion to NOT hit your tires with the mower deck.

A wider deck than the tractor is a good thing. It covers the wheel tracks when cutting.

 

[Smokeydog]

We use a 6’ finishing mower on our Kubota B26. Wife can expertly mow close to rock borders, walls, fences, trees, etc without having to trim or weedeat. Love the rear discharge finish mowers. So like having the mower wider than tractor.

Do run Oregon gator blades the give a better cut and stay sharper than the OEM blades. Take the blades off to sharpen you can nest them and easily see if one is bent. Go thru a set of blades every two to three years. Occasionally bend a blade. Don’t forget to grease blade spindles.

 

[chim]

I looked up the HDTH-8 and it looks very similar to most RFM's. To check the alignment of things, I'd start with a good flat surface like concrete or a nice paved spot. After the normal safety advice (tractor not running, block wheels, ect.) start by making sure that all four gauge wheels have the same number and size of spacers between the wheel yokes and the bottoms of the arms.

Then measure between the bottom of each blade and the flat surface. Start taking those measurements with each blade rotated perpendicular to the direction of travel. Then rotate them 180° and measure again.

Then rotate the blades 90° and measure, then rotate them 180° and measure again.

If the measurements consistently don't match up left to right, it would make a sort of "sawtooth" cut. A difference in front-to rear measurements might make some sort of signature as it mows, like a shallow swale scooped out pattern a little narrower than the blade length.

Measure from the flat surface to the tip of each of the nuts (or bolts) that hold the blades on. These should all be the same. If not it would suggest there's a bend in an arm or the deck where it supports the spindle.

Another possibility would be a bent blade. If odd measurements such as the same end of the blade is consistently higher or lower at the 4 points of rotation. the blade is bent. In my 34 years using at least 6 different decks I never bent a blade (even with managing to shear off a spindle in one case).

 

[allenport]

Good info.

To me, without seeing the pictures, it really sounds like the mower attached to the tractor (lift arms) are out of alignment. There should be a lift arm on the tractor that is adjustable. Turning it may require some effort. If you are on a level surface, and eyeballing which side the uneven cut is on, with the mower deck down, may reveal that adjustment issue.

You mentioned swaying. That is also the mower attaching to the tractor. There should be further adjustments on the hitch swings to tighter that up. These are "arms" that the mower is attached to. Lift the mower up, and attempt to rock it back from side to side. There should be just enough motion to NOT hit your tires with the mower deck.

A wider deck than the tractor is a good thing. It covers the wheel tracks when cutting.

 

[allenport]

Pictures coming soon.
The lift arms....aah. I do recall seeing somewhere that this was the solution to one side cutting lower. I recall telling my handyman to see about adjusting that, and it seems the lift arm was 'frozen'. I mean...maybe rusted or something. This I'll have to check and get back to you.

I don't have a swaying problem anymore. This only happened when my handyman initially hooked up the mower.

 

[old and tired]

But where the 3 point arms attach to the mower deck, those should have their own "float" built in.
The pins should move up and down freely... at least they do on my RDTH-72 Bush Hog finishing mower.

So photos of how it's connected to the tractor, would help.

 

[workinonit]

Yep, unlike zero turn mowers, FMs ride on the deck wheels. Most of them have some sort of swivel pin type hook up so they can float. If it's riding on the lift arms, that's your issue. Basically all the 3 point hitch is for is to pull it along and lift it. When down it simply rides with the ground terrain.

 

[allenport]

I'm reporting back with how this problem was fixed. Sorry it took so long but this site was down (at least for me it was) and then time slipped away.

It turned out to be a missing bolt from the castor support bar. I don't know why this wasn't obvious, especially in May when I had the tractor serviced.

Now it mows pretty evenly.

Unfortunately, I now have a new problem that occured today. Always on a weekend. I might put up a new thread, but I won't be able to explain the problem well enough and probably won't understand the answer either. It's awful to live on a farm when you have no mechanical knowledge or talent.

 

[old and tired]

...It's awful to live on a farm when you have no mechanical knowledge or talent.

Well, you got to start somewhere and now is a good time.

The most amazing thing I've seen (not sure if it was here or on OTT) but a group of us were able to explain how to set up Hydraulics to a farmer in Ukraine (I think that was the country) on his Kubota! He English was marginal but we managed!

If you are a little bit thicker skin - and you can answer (or ask for clarification, when needed) about the problem... I'm sure "we" can walk you through it!!

Is it electrical, mechanical or hydraulic in Nature?