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Issue with poor quality cut while mulching with my ZT-52HD

#1

jpollman

jpollman

Hi folks!

I'm on my second season with my Gravely ZT-52HD. I bought the mulch kit for it and it worked fine last season. In the fall, I bought a set of Gator blades and it did a wonderful job mulching up the leaves in the yard. This season though, I'm having a problem with the deck not cutting cleanly. It is leaving a stripe of poorly cut grass that appears to line up with where the center and right hand blades cut. I've kept the blades sharp and one of them appeared to MAYBE be a little bent but it probably wasn't. Just in case, I bought a brand new set of mulching blades at my local Gravely dealer a couple weeks ago. Even brand new, I took a fine file and touched them up and made sure that they were good and sharp. It's still doing it!

I went through the procedure to level the deck side to side and set it to specs for front to back. It's still doing it! I bought a mower jack and raised up the front and climbed around underneath and there are NO signs of any blockages and the blades are all lined up and everything appears to be in order. I'm completely stumped!

My next plan of attack is to remove the mulching baffles and put the original blades back on it and cut the grass in discharge mode and see what happens.

Has anyone else had an issue like this and figured out what the problem was?

Thanks in advance for any input!


#2

M

Mikel1

Just a thought but is that right side blade pulley harder to turn than the other?


#3

lawn mower fanatic

lawn mower fanatic

These are some common reasons:

  • The blade tips are worn.
  • Your overlapping may be insufficient: The tires push down grass during each pass. If you line up your tires with tire marks from the previous pass, the grass does not get a chance to stand back up during either pass. Overlap more than the width of your tires on subsequent passes. This will allow the blades to draw up the trampled grass from each previous pass and should produce a nicer looking cut.
  • Right hand turns: Twin-blade mower decks are designed with the discharge on the right side. The left blade is positioned slightly forward and in front of the right blade. During left turns this cutting overlap is maintained. This provides cutting overlap when traveling in a straight line. The tractor operator should therefore make mostly left-hand turns when cutting grass.
  • Improper cutting deck adjustment: This can produce a vacuum imbalance that, under certain circumstances, causes airflow to push outwards from the front of the cutting deck. Consult your tractor Operator's Manual for specific Deck Leveling and Deck Engagement adjustments pertaining to your specific model tractor.
(Uncut Strip - Riding Mower)


#4

Carscw

Carscw

Check the blades again turn them each twice to make sure both ends line up with the blade next to it

(( racing is the only sport that you need two balls ))


#5

djdicetn

djdicetn

lawn mower fanatic said:
These are some common reasons:

  • The blade tips are worn.
  • Your overlapping may be insufficient: The tires push down grass during each pass. If you line up your tires with tire marks from the previous pass, the grass does not get a chance to stand back up during either pass. Overlap more than the width of your tires on subsequent passes. This will allow the blades to draw up the trampled grass from each previous pass and should produce a nicer looking cut.
  • Right hand turns: Twin-blade mower decks are designed with the discharge on the right side. The left blade is positioned slightly forward and in front of the right blade. During left turns this cutting overlap is maintained. This provides cutting overlap when traveling in a straight line. The tractor operator should therefore make mostly left-hand turns when cutting grass.
  • Improper cutting deck adjustment: This can produce a vacuum imbalance that, under certain circumstances, causes airflow to push outwards from the front of the cutting deck. Consult your tractor Operator's Manual for specific Deck Leveling and Deck Engagement adjustments pertaining to your specific model tractor.
(Uncut Strip - Riding Mower)
Click to expand...

jpollman,

Very good points to consider given by user lmf!!! Add to that the cardinal rule(especially in the beginning/middle of the mowing season versus the mowing you did last year at the end of the season)....cut frequently(how long do you wait before mowing again?)....and how tall is the grass before mowing.....and never cut more than 1/3 of the total height of the grass(even more important when "mulching"). Also, do you still have the OEM blades that came on the Gravely(or did the dealer install mulching blades and keep the originals)??? I would think, since you are buying blades from your dealer, they would be absolutely certain that you got the "correct length" replacement blades, but the point user lmf made about "blade overlap" could be part of the problem if the mulching blades are slightly shorter than the 52" deck's OEM blades.


#6

jpollman

jpollman

Thanks guys!

I'm still fighting this issue. I've been mowing pretty much every seven days. I cut my own lawn at about 2-1/2" and it looks pretty good. I took the machine down to my fathers place and cut his lawn. I have been cutting his at 3" all summer and it was pretty good but not as good as mine. The last cut on his, I cut it at 3-1/2" and it was terrible today. Very uneven cut! I only cut about half the lawn (it's about 1.75 acres) and had to leave. I'm going to go back tomorrow and step it down to 3" and recut what I did today and see what happens.

I'm thinking that the loss of vacuum seems logical because it does seem to get worse as the cutting height increases. I was using the original blades from when I bought the machine last year and been keeping them sharp. But a couple weeks ago, I went to another Gravely dealer and asked for a set of "mulching blades" for my ST-52HD and the ones he gave me appear to be the correct size. Although they were brand new, I did give them a few strokes with a nice sharp fine file to give them a very nice sharp edge.

I bought a mower jack and lifted it up when I installed the blades and made sure that they were all lined up when I was done. I don't know how long they stay that way once you start cutting, but I figured that was a good place to start. :) I also spent quite a bit of time the other day going through the deck leveling procedures and have a blade height gauge. I got it good and level left to right, and within specs for front to back. The manual says that the front of the blade should be about 1/8" lower than the back. It also says that if you "heel" the deck with the rear of the blades slightly lower than the front, it will use a little more engine power, but it can result in a cleaner cut. Maybe I'll try that next.

I'll let you know if and when I figure it out. Thanks again!


#7

djdicetn

djdicetn

jpollman said:
Thanks guys!

I'm still fighting this issue. I've been mowing pretty much every seven days. I cut my own lawn at about 2-1/2" and it looks pretty good. I took the machine down to my fathers place and cut his lawn. I have been cutting his at 3" all summer and it was pretty good but not as good as mine. The last cut on his, I cut it at 3-1/2" and it was terrible today. Very uneven cut! I only cut about half the lawn (it's about 1.75 acres) and had to leave. I'm going to go back tomorrow and step it down to 3" and recut what I did today and see what happens.

I'm thinking that the loss of vacuum seems logical because it does seem to get worse as the cutting height increases. I was using the original blades from when I bought the machine last year and been keeping them sharp. But a couple weeks ago, I went to another Gravely dealer and asked for a set of "mulching blades" for my ST-52HD and the ones he gave me appear to be the correct size. Although they were brand new, I did give them a few strokes with a nice sharp fine file to give them a very nice sharp edge.

I bought a mower jack and lifted it up when I installed the blades and made sure that they were all lined up when I was done. I don't know how long they stay that way once you start cutting, but I figured that was a good place to start. :) I also spent quite a bit of time the other day going through the deck leveling procedures and have a blade height gauge. I got it good and level left to right, and within specs for front to back. The manual says that the front of the blade should be about 1/8" lower than the back. It also says that if you "heel" the deck with the rear of the blades slightly lower than the front, it will use a little more engine power, but it can result in a cleaner cut. Maybe I'll try that next.

I'll let you know if and when I figure it out. Thanks again!
Click to expand...

I picked up a mulch kit for my Pro-Turn 152 this morning to deal with the clippings from a very mild/wet July/August here in middle TN that has made the grass grow very fast and very thick. It came with Gravely mulch blades and as I understand it Gator blades are not designed to be used with a mulch kit, rather with regular side discharge(I thought about that and still may give them a try). I too am toying with the idea of changing the pitch of my deck to have the rear blade tip lower(referred to in our Gravely manuals as "heeling the deck") but I only want to try one thing at a time. Iv'e bben very pleased with the OEM blades' cut with normal side discharge as far as cut quality, but the grass clippings have become a nuisance(I have mowed over them 4-6 times and made them barely noticeable). I hope the mulching kit will help mid season(when the grass is growing fast & thick) and will probably remove the mulch kit at the end of the season and go with the OEM blades or Gator blades with side discharge for Spring, early Summer and Fall cutting. I'll let you know what kind of results I have.


#8

djdicetn

djdicetn

djdicetn said:
I picked up a mulch kit for my Pro-Turn 152 this morning to deal with the clippings from a very mild/wet July/August here in middle TN that has made the grass grow very fast and very thick. It came with Gravely mulch blades and as I understand it Gator blades are not designed to be used with a mulch kit, rather with regular side discharge(I thought about that and still may give them a try). I too am toying with the idea of changing the pitch of my deck to have the rear blade tip lower(referred to in our Gravely manuals as "heeling the deck") but I only want to try one thing at a time. Iv'e bben very pleased with the OEM blades' cut with normal side discharge as far as cut quality, but the grass clippings have become a nuisance(I have mowed over them 4-6 times and made them barely noticeable). I hope the mulching kit will help mid season(when the grass is growing fast & thick) and will probably remove the mulch kit at the end of the season and go with the OEM blades or Gator blades with side discharge for Spring, early Summer and Fall cutting. I'll let you know what kind of results I have.
Click to expand...

jpollman,
Well I've cut twice since installing the mulch kit on my Pro Turn 152(once with the grass VERY wet at 3 1/2"....the deck was "filled with wet clippings when done, but very nice cut in the front and a couple of clipping clogs dropped in the back yard....and then again @ 2 1/2", where I normally cut, with the grass good & dry with VERY good results...and a LOT less clippings undeneath the deck when done). So far I'm pretty happy with the mulch kit, but I'll keep you posted as to how it continues to perform. Have you ever figured anything out on yours???


#9

A

Amm0622

jpollman said:
Hi folks!

I'm on my second season with my Gravely ZT-52HD. I bought the mulch kit for it and it worked fine last season. In the fall, I bought a set of Gator blades and it did a wonderful job mulching up the leaves in the yard. This season though, I'm having a problem with the deck not cutting cleanly. It is leaving a stripe of poorly cut grass that appears to line up with where the center and right hand blades cut. I've kept the blades sharp and one of them appeared to MAYBE be a little bent but it probably wasn't. Just in case, I bought a brand new set of mulching blades at my local Gravely dealer a couple weeks ago. Even brand new, I took a fine file and touched them up and made sure that they were good and sharp. It's still doing it!

I went through the procedure to level the deck side to side and set it to specs for front to back. It's still doing it! I bought a mower jack and raised up the front and climbed around underneath and there are NO signs of any blockages and the blades are all lined up and everything appears to be in order. I'm completely stumped!

My next plan of attack is to remove the mulching baffles and put the original blades back on it and cut the grass in discharge mode and see what happens.

Has anyone else had an issue like this and figured out what the problem was?

Thanks in advance for any input!
Click to expand...

I have had the EXACT same problem with my two year old 452! Numerous complaints to Gravely and nothing has been done. They keep trying to tell me I'm the only one who has had this problem and keep making it sound like I don't know how to mow. It's extremely frustrating to have to mow properties twice to eliminate the uncut strip. Guys...the strip is the entire length of each and every pass. Gravely provided all the blades I have tried, so they're all brand new, I have paid to have them check and adjust the deck, and all I get in return is a "well, no one else has made this complaint so it's not an issue we've ever had." Long story short...selling this $11,000 heap and going back to the JD. Adios Gravely!


#10

wjjones

wjjones

Amm0622 said:
I have had the EXACT same problem with my two year old 452! Numerous complaints to Gravely and nothing has been done. They keep trying to tell me I'm the only one who has had this problem and keep making it sound like I don't know how to mow. It's extremely frustrating to have to mow properties twice to eliminate the uncut strip. Guys...the strip is the entire length of each and every pass. Gravely provided all the blades I have tried, so they're all brand new, I have paid to have them check and adjust the deck, and all I get in return is a "well, no one else has made this complaint so it's not an issue we've ever had." Long story short...selling this $11,000 heap and going back to the JD. Adios Gravely!
Click to expand...



Does the blade tip on your deck set just bellow the leading edge of the deck, or even with it? I never mulch cut any yard its a pita, and harder on your equipment but some people like it so.


#11

A

Amm0622

wjjones said:
Does the blade tip on your deck set just bellow the leading edge of the deck, or even with it? I never mulch cut any yard its a pita, and harder on your equipment but some people like it so.
Click to expand...

It appears to be just below the front of the deck, and level with the sides and back of the deck. If anyone has any ideas, I'd be glad to hear them. It's frustrating mowing every yard twice just to remove a 1' strip of grass that has been left behind on every pass. Thanks guys!


#12

wjjones

wjjones

Amm0622 said:
It appears to be just below the front of the deck, and level with the sides and back of the deck. If anyone has any ideas, I'd be glad to hear them. It's frustrating mowing every yard twice just to remove a 1' strip of grass that has been left behind on every pass. Thanks guys!
Click to expand...



Usually if its just below the leading edge of the deck it cuts pretty good becuse it contacts the grass before the deck pushes it down. Have you checked all of your blade spindles, and idler pulleys? They could be slowing down your blade tip speed enough to cause this problem if one of them is going bad. Also check the deck baffle to see if it might be bent down.


#13

A

Amm0622

wjjones said:
Usually if its just below the leading edge of the deck it cuts pretty good becuse it contacts the grass before the deck pushes it down. Have you checked all of your blade spindles, and idler pulleys? They could be slowing down your blade tip speed enough to cause this problem if one of them is going bad. Also check the deck baffle to see if it might be bent down.
Click to expand...

I removed the baffles as I could not notice any difference in cut quality other than it left clumps after awhile due to the build up of grass on the baffles over time dropping off. The spindles and pulleys...I can't say that I personally have as I'm not familiar with the mechanical side of things that particularly well, but I did have the Gravely dealer look at it and they did adjust those along with the engine speed (or something related to that). They told me they had adjusted the engine and I do remember them saying to get the appropriate blade speed out of it, but I was still having the issue immediately following the "repair." I swear, I'm almost positive on this thru various measuring and tests I have done that the two blades leaving the strip do not overlap. I understand, and the dealership even told me this like I'm a complete moron, that it may not look like they are due to being offset, but when I get out the tape and make various marks on the floor with levels and what not...they don't even come close to overlapping. I can't even get Gravely to begin to look at it for that theory. I don't know if I bent something causing it to go whack-o but either way, it doesn't cut right. It's all good though....the John Deere guy is coming to take it anyway and place my new mower in the garage this week.


#14

wjjones

wjjones

Amm0622 said:
I removed the baffles as I could not notice any difference in cut quality other than it left clumps after awhile due to the build up of grass on the baffles over time dropping off. The spindles and pulleys...I can't say that I personally have as I'm not familiar with the mechanical side of things that particularly well, but I did have the Gravely dealer look at it and they did adjust those along with the engine speed (or something related to that). They told me they had adjusted the engine and I do remember them saying to get the appropriate blade speed out of it, but I was still having the issue immediately following the "repair." I swear, I'm almost positive on this thru various measuring and tests I have done that the two blades leaving the strip do not overlap. I understand, and the dealership even told me this like I'm a complete moron, that it may not look like they are due to being offset, but when I get out the tape and make various marks on the floor with levels and what not...they don't even come close to overlapping. I can't even get Gravely to begin to look at it for that theory. I don't know if I bent something causing it to go whack-o but either way, it doesn't cut right. It's all good though....the John Deere guy is coming to take it anyway and place my new mower in the garage this week.
Click to expand...



I removed the baffles on mine once too it was a big mistake. How short, or high are you cutting the grass? Is there any chance they gave you the wrong blades? If you line them up tip to tip there should only be a very small gap between them. Some mowers blades overlap, and some dont, and some are timed to overlap without hitting each other. I would jack up the mower, and try the tip to tip line up first, and go from there.


#15

exotion

exotion

Has anyone tried tightening the belt? The scag I used to use needed the belt super tight or the blades would slip and leave the uncut strip between the blades. I would check belts and pulleys make sure spindles are greased same with pulleys and they spin freely with no hesitation or wobble. The belt might be old and worn?


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