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Discussion Starter · #1 ·
I've started this thread as a response to a question about quality of cut on the older Kubota G-series. I noticed a lot of scalping and uneven cut initially. I thought it was normal for a wide (60") deck. But it's not and can be corrected. I had a lot of problems getting mine right mainly due to set up issues. I'm still not sure it's completely right but I'll share what I've learned along the way and hopefully others will as well.

My G1900 has the 60" rc60-g20 deck. My deck is one of the later ones built having the lift assist springs in the back that apparently many do not. These springs hold some of the weight of the deck contributing to better traction I suppose.

I have one of a very few I'm sure 2009 g1900's. It was sold new in January 2009. I got it with 5 hours so clearly I received it as new from the dealer. My point being if mine could be set up wrong then so could any other that was used more or less.

According to my manual the 54" and 60" decks are very similar with slight differences in adjustment and mounting for the 44" and 48" decks. Mine is very deep which keeps it from clogging in any circumstance I've been able to put it through.

The deck has 6 wheels. The front 3 are anti scalp rollers. They should all be the same size (and part number). There is a fourth anti scalp roller at the center rear (inside the deck housing) of a different size and part number to the front three. There are two at the rear on either side that are adjusted to determine cutting height. These are the only two that should be in constant contact with the ground. These wheels swivel slightly to either side.



The deck mounts to the tractor in three places (or two if you have an older model). Those being the assist springs, the rear links (lift rod attaches to these), and at the front the front links. The front link is a single piece on the 54 and 60 inch decks and two parts on the smaller ones.

The lift springs attach only one way but need to be adjusted in accordance with the sticker on the deck depending on where you set the cutting height.

The real links have two sets of holes for attaching to the tractors lifting mechanism. The 54 and 60 inch decks should use the front set of holes and the smaller ones the rear set. The rear links also mount to the tractor frame with two sets of holes. The larger decks use the rear of the two sets and the smaller ones mount to the front of the two sets.

So for the larger decks you should mount on the x's:

O X X O

And for the smaller decks:

X O O X



The front of the deck mounts to the front of the frame by the front linkage. This determines the height off the ground for the front of the deck. My operator's manual says there should be 15.4 inches from the front rod to the holes that attach to the deck. That must just be a starting point because it wasn't even close on mine. It was providing no lift whatsoever for the front of the deck and it was riding on the anti-scalp rollers.

The manual is a little funny (and brief) in it's description of the adjustment process. One line went something like this: "if it do not so adjust the rift rods". I was picturing that Japanese soldier on Gilligan's Island writing that as I was trying to get the thing adjusted. I assume that's supposed to be "lift rods".

Which lift rods they are referring to is lost on me. The front ones or the ones that attach to the hydraulic lift mechanism? I assume the front link because I don't think the lifting mechanism is supposed to carry any weight once the thing is down on the ground. Then again in the parts manual the lift rods are the pieces that attach to the lifting mechanism and the front piece is called the "front link".

That's an overview of what I know, and like everything else I know it could very well be wrong so just say so.

My mower was completely wrong in almost every area that I've described above. One of the front rollers was wrong and a lot smaller than it should be. The rear center roller was missing. Of most consequence one of the rear swivel wheels was wrong and of a different height so it could never mow level like that. The deck was mounted in the wrong holes (too far forward) which resulted in very poor traction. To the dealer's credit all this was corrected under warranty.

I continued noticing scalping and that the grass was much shorter than it should be on the next to the highest setting. It was set for 3.5" and mowing less than 2" with uncut strips between the blades. That's when I realized the 15.4 inches mentioned in the manual is either wrong or a starting point because the front of the blades was way too low and I had to shorted the length of the front link considerably to lift the front of the blades to near level. On other equipment I've owned I found it cut best when the front of the blades was slightly lower (less than 1/4") than the back.

I took great care to adjust both sides of the front link the same but I found that the left side was about 1/2" lower than the right. I've adjusted them differently now and gotten them much closer but the left side of the front link is about 3/4" shorter than the right side as a result. This doesn't seem right but it's the stage I'm at right now.

It does cut much better. As good as anything else I've used. The reason I was scalping was that the deck was cutting so low. Measure the grass and see if it is close to the setting you are using on the mower.
 

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My set up does not appear to have all those choices.
I always thought the link arms that attach to the front of the tractor frame were too long on my g5200 but I was never able to adjust them enough to get the rollers off the ground on the leading edge of the mower.

I would imagine that the helper spring(s) were added to take some of the load off the ram which is at a mechanical disadvantage. My old G5200 with simular lift geometry had a spring to assist the manual lift which is near impossible without it.



The "anti-scalp" rollers have been totally worn out on every G series tractor I have ever seen that had more than 100 hours on the meter. They don't get like that by touching the ground only occasionally. So my question is this: Are any of the mowers adjusted/set up correctly? If not why not? Lost in translation?

As you can see my deck has a very pronounced nose down attitude.
 

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My front linkage measured approximately 15.4" (center of the front rod to center of the rear hole), but I have 1/4" of wear in the front rod, and a little more than that in the rear hole. So, my actual/real measurement is off by more than half an inch.

I have always considered the outer front rollers as gauge wheels, and the cutting height has always been lower than it was supposed to be. In fact I have made some brackets to make the outer front rollers lift the deck higher to increase cutting height.

If the front linkage determines the lift off the ground for the front of the deck, then it should have to be adjusted every time you want to change cutting height. I've not seen any directions to adjust the front linkage for a cutting height adjustment.

To me, all the front linkage is for is to pull the deck forward with the tractor.
 

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Discussion Starter · #4 ·
I can't imagine that the front guage wheels are supposed to ride the ground. That would make the maximum cutting height about 2" on mine. Why else would the front link be adjustable?

All mower decks are basically the same. Every other one I've ever owned required that the deck be basically level front to back and side to side. From my manual:

"Set the mower at cutting height and adjust both front links equally with the turnbuckles so that the mower blades are level"

Does that mean front to back or just side to side? I don't know. It goes on to say:

"This means that x-y=a as illustrated"

The diagram shows x as the distance of the bottom of the center anti scalp wheel bracket to the ground. Y is the bottom of the deck lip at the rear guage wheel to the ground. A is .3" (8mm) for the 54 and 60 inch deck and .4" (11mm) for the smaller ones. So the front edge of the deck should be slightly higher than the rear edge. I don't see any way to adjust that other than the front links. I'll try and scan that page for you all. It's still not very clear to me.
 

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Discussion Starter · #6 ·
If I adjust my deck to the x-y=a formula listed above it puts the front of the blades about 3/4" lower than the back. The front guage wheels are off the ground about 1/2".
 

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The diagram shows x as the distance of the bottom of the center anti scalp wheel bracket to the ground. Y is the bottom of the deck lip at the rear guage wheel to the ground. A is .3" (8mm) for the 54 and 60 inch deck and .4" (11mm) for the smaller ones. So the front edge of the deck should be slightly higher than the rear edge. I don't see any way to adjust that other than the front links. I'll try and scan that page for you all. It's still not very clear to me.
That all makes lots of sense as that is pretty much how my Simplicity deck rides, however I was never able to achieved that nose up or for that matter even level attitude on my G5200. That is why I never used it for more than rough cut which it was good at. The finish mowing I left up to my Allis. Hopefully I can get this "new" Kubota sorted out... If not I am afraid it is out of here.
 

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Phil, please post some pics of the front attachment area. I'll take a look at my G4200 later today. Mine sits good & level.
Daniel, you will have to forgive the quality of the photo as it is very humid out today and my lens kept fogging. I don't know if your G4200 is like my G5200 was but about the only real difference I can see is mine had turn buckles which could be adjusted with the link in place. The deck looks relatively level only because I have 2x4 blocks under the leading edge. Having 15"+ long links to elevate the deck by pulling it forward against a canterlevered lift cradle seems like a very serpentisious way to get it accomplished. After all have you ever tried lifting a long pole by standing on the end and lifting with a rope running nearly parallel to to it? It can be done but it is a real gut wrencher even with a light weight but if you increase the angle just a little bit it is easily managed. I just think it is a very flawed design if this many people can't resolve it.
 

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Discussion Starter · #10 ·
I worked on it a little today. I evened out the front link and lengthened it a little. It is still quite a bit shorter than the 15.4" though.



As you can see the front rollers are suspended about an inch off the ground. As far as lifting the deck from the front link goes, you are really not lifting anything. It's just preventing it from dropping and that's not exactly the same thing.

The left side of my deck is about 1/4" lower than the right side no matter what I do. Maybe I'm just expecting too much.
 

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Phil, I didn't get time to look at my Bota today, but will try tomorrow. I tend to think that your front link arms have fatigued a bit at the angled areas & allowed the drop. I "think" mine is set up the same way. Yes, they should be equipped with turnbuckles to allow fast simple adjustment. I would try to find some heavy duty turnbuckles that could be put on these arms.
 

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I am not sure exactly what the dimensions are supposed to be on the 48" mower but I propped the leading edge up with two 2x4's and took off the the left hand link. It measured c-c pin to pin, 19" so I am not really sure what the 15.4" measurement is supposed to be. I did however find that the lock nut was set at approximately 15" from the center of the front pin. The threads were pretty well welded with rust so I soaked with blaster and clamped it in my 60# vise. It was a real PITN or more accurately PITB to break loose but I finally got it moving and shortened to where it snugged up to the lock nut that looked to be in the original position which just so happens to be about as short as it can go without the end of the threaded rod contacting the bolster on the front of the mower. I did not measure but the front edge of the mower now appears to be approximate 3" off the ground. When I readjust the right side tomorrow I am going to coat the screw threads with anti seize compound on the right and the left. After straining to lift the vise out of its storage place and straining to break the threads loose I hope I can stand up tomorrow.
 

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Phil, I didn't get time to look at my Bota today, but will try tomorrow. I tend to think that your front link arms have fatigued a bit at the angled areas & allowed the drop. I "think" mine is set up the same way. Yes, they should be equipped with turnbuckles to allow fast simple adjustment. I would try to find some heavy duty turnbuckles that could be put on these arms.
I would not be surprised if your mower already has the turnbuckles as my 5200 did.
 

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I worked on it a little today. I evened out the front link and lengthened it a little. It is still quite a bit shorter than the 15.4" though.



As you can see the front rollers are suspended about an inch off the ground. As far as lifting the deck from the front link goes, you are really not lifting anything. It's just preventing it from dropping and that's not exactly the same thing.

The left side of my deck is about 1/4" lower than the right side no matter what I do. Maybe I'm just expecting too much.
Mc25a, it looks as if you are getting there... On my mower the guide roller on the left is about 2 inches further from center line than is the right roller due to the discharge chute... That could make a difference if that is where you are measuring. How far is the leading edge of your deck off the ground on each side? that I would think would be the true measurment. You may want to check the height of the deck at the rear wheels...That may be the determining factor. As you can see from the photo below mine is looking a lot like yours (only much dirtier) but does have a little more nose up attitude...that BTW could be because the PO has the tires in front pressured up rock hard and I have not yet reduced the pressure down to the 10-12 psi I assume they are supposed to be inflated. My rollers are about 2 " off the ground but they look like they are attached higher on the deck than are yours. The PO is supposed to be looking for the tractor & mower manuals this weekend that he packed up while moving. Hope he finds soon as I would like to get educated on this unit.
 

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Discussion Starter · #15 ·
Phil,

I'm actually measuring from the blade itself. The 15.4" measurement applies to the 54 and 60 inch decks for the 1800 and 1900. I doubt it would be the same for you. Anyhow to get it as level as it is in the picture I'm at about 14".

It would be easier to measure the leading edge of the deck to the ground but I don't think it's meant to be level all the way around. That's why I've decided to measure the cutting edge of the blade instead.
 

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mc25a, you are right. the blades tell the truth. 14"?! WOW that is way shorter than the published dimension. I have made a lot of headway with this mower. I never could get the left front wheel to leave the ground on my G5200 even with the mower raised. Thanks for publishing the instructions . I always figured it had to do with the length of the front links.
 

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Gents,

I want to thank ALL you for this conversation!! I'm going to try shortening my front linkage to lift the front of my deck up.

Ed Fulton
 

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Phil, my G4200 DOES have the large turnbuckles made onto the front arms. Mine is riding level & has plenty adjustment left yet.
Mine are all but bottomed out on the bolsters but they are far better that before.. I tried cutting with it and it did ok on by centipede grass and mixed Bermuda, but even with it raised up as far as it would go it cut way too low on my neighbor's plush St. Augustine. I will have to go over and beg forgiveness when she gets home. I like to do pro bono Work in the neighborhood and don't want people running me off for butchering their yards.
I will just have to remember to cut thich carpet with my Allis.
 

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mc25a,

Two ideas for consideration:

1) Lower the center roller one or two positions. This will attach the front linkage lower and allow it to lift the deck higher??

2) One could install suspension chains from the tractor frame to the front of the deck to set the cut height wherever you want it.

I do thank you and all the guys for their input on this subject. I always figured the Japs confused centimeters and inches with their cutting height settings.
 
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