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scoob8000

Hydro vs Manual deck height

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scoob8000

So it's that time of year again where I'm fighting with my 42" SD to get a nice cut.

(Still fighting with blow-out and cutting too low even on the highest setting)

 

Talking with a co-worker something got me thinking about a dumb question!

 

The manual manuals have a knob that adjusts the deck height when you have the deck down..   What limits that height on the hydro models like mine?   Should I not be putting the hydraulic down the whole way when I mow?

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Ed Kennell

If you know the model number of your deck, you can download the manual that will have detailed instructions  on how to set the height and level the deck.

Typically the rear deck  wheels are used to adjust the cut height on manual and hydraulic lifts.

 

Not sure what "blow out " is.

Edited by Ed Kennell

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scoob8000

Ed,

 

I have it leveled as per the book.   Front tip of blades 1/8" - 1/4" lower than the rear tip.

 

The blow out I speak of is the massive amounts of grass clippings that come out front under the front of the deck.   It's enough that after one or two passes my left shoe has grass all over it.    It's an issue I've been fighting with since I got this tractor.   As far as I can tell, I have everything adjusted to spec.   But even on the highest setting, I'm still scalping my yard in spots.

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Ed Kennell

Do you have the FORK around the rod when you connect the deck to the attach-a-matic?    This is what keeps the deck level when you adjust the rear height wheels.

Edited by Ed Kennell
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pfrederi

The blow out will be worse the higher you set the cutting height. Both my 48sd do that i have to keep a small brush with me to keep the engines blower intake clean.  Rear discharge don't do that.

 

i do not understand your scalping problem.  i mow some areas that are pretty rough (former pasture) but don't have a big scalping issue.  Are your rollers worn either in outside diameter or are of the inner bushings /axle worn which would make them less effective.  Also is your scalp issue going over conical bumps (less than deck width or going over ridge lines (longer than deck width.  If your deck wheels and rollers are in good shape it is hard to scalp.... 

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scoob8000

Ed, my co-worker mentioned checking the fork too.   It is engaged properly.   I've had it miss in the past when putting the deck on.   Usually when I pinch my fingers.  :)

 

pfrederi,

 

What makes me think it's deck/adjustment related is I only get this on my 42" deck.   I have a 48" also which I get nearly nothing blowing out the front.

The scalping is in spots like you mention, but I've got marks where it cuts two low here and there.    I'm thinking about replacing all the front rollers and trying to get a slightly bigger gauge wheels for the back.

 

I go thru this every season.   The 48" deck cuts beautifully, but I've welded it so many times and patched it I know it's days are numbered.   The 42" is pristine so I keep trying to use it.

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pfrederi

How original is the 42...Are they the correct blades???  42 SD and 42 RD use different blade sets

 

anything bent??  When you have the deck off upside down are the blade tips at a  matching level.  A bent deck shell  (or incorrect spendle)may have one blade out of alignment.

 

I have had to shim some blades to get the tips to come out even

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clueless

After I bought my first WH, a used B80 I could not get it to cut right, uneven, blowing out the front, scalping. After a month of trying to get it adjusted I gave up, took it to the local WH dealer. The old man who worked on them ask what all I had tried, I showed him. The first thing he said was, the lift adjustment knob is not for the deck it is for other attachments, if your using it to help adjust your deck height, you will never get you deck completely adjusted right. He adjust my deck, and put a new set of blades on, it still is the best grass cutting WH I've ever owned. The old fellow gave me a lot of WH advice over the years, I sold the B80 and he passed away a few years ago, I miss them both. Get the deck adjusted right and leave the knob alone.  

My '88 312-8 that I use as a back up mower didn't even come with the lift adjuster from the factory.

Edited by clueless
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scoob8000

pfrederi,  the deck and spindles are original.   The original blades were severly worn and cracking at the tips where they curve up.   I replaced them with gatorblades that my dealer cross referenced them to.

 

Tips are level as best as I can tell.    I'm pretty sure once last year I put the old blades back on to see if my gator blades were the issue.

 

clueless,  Mine is a hydro, so no knob.   I was just curious if it was used for the decks on the manual models.

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Ed Kennell

Can you post  pictures of the rear wheel height adjustment arrangement and the deck support carriage  at the attach-a-matic?

     Something is just not making sense...a 42" scalps and a 48" does not.

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can whlvr

I have several decks from 36 to 48,they all cut different and some do as you say,i found the 48,s cut best

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Tankman

I use 48" SD decks, never a problem. Nice cuts even on lousy turf.

Ditto, same with the 42" SD decks I've owned in the past.

 

Are the wheels correct size? Any rollers worn. wobbly?

 

Be sure to post THE FIX for the problems.   :wacko:

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scoob8000

Ed, I'll grab some pics in a day or two here.   It's supposed to rain pretty good tonight.

 

I mowed last night and went to relevel the blades again.   I know I had them 1/4" from front to back last season.  But with the deck down and in the highest cutting setting I was nearly 1" from front to back.   It was the front of the blades digging in because they were so low that was scalping.

 

I tightened up the adjuster and brought it closer to 1/4".    Scalping is fixed, but that worsened the amount of grass flying out the front of the deck.   (bangs head)

 

 

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pfrederi

The gator blades may be a part of the blow out issue especially if they are not correct for SD  :think: 

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Ed Kennell

Great, good to know you solved the scalping problem.     Now the blow out.      Are the baffles in the deck?  Any blockage by grass build up?  Have the spindles been replaced?

I am not familiar with the Gator Blades. If they are a mulching blade, they are  probablynot designed to throw the grass to the right.

Edited by Ed Kennell

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scoob8000

Ed,  They are a mulching/discharge/all in one type blade.   They look like a standard hi lift blade, but with cutting/mulching edges on the lift "wing".  

 

Last mow I stuck my old original blades back on and honestly not really any difference.   Just bigger clippings.

 

Can someone measure the rough diameter of their spindle pulleys on a 42" SD.  I don't have a model, but mine is a 1994 model.    I don't know why I never thought about it, but the spindle pulleys on my 48" are quite a bit bigger than the 42".   Maybe if they're the wrong size, they're spinning too fast?   (Grabbing at straws)

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shallowwatersailor

I have mentioned this before on other mower deck issues. The best tool that I have found - and easiest to use - is this sold by Sten, JD, etc. It beats trying to measure blocks, etc when setting/checking blade height. You can easily tell if a wrong spindle has been installed. I only wish that the Cutting Height was on both sides. But I guess, now that I mention it, I could do that myself.

 

DSC07974.thumb.JPG.16d4f19461f998a4e34ee869e750332c.JPG

 

DSC07978.thumb.JPG.bd9ed419d039af8104ac7d35e2fcfb4e.JPG

 

 

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clueless
20 minutes ago, shallowwatersailor said:

I have mentioned this before on other mower deck issues. The best tool that I have found - and easiest to use - is this sold by Sten, JD, etc. It beats trying to measure blocks, etc when setting/checking blade height. You can easily tell if a wrong spindle has been installed. I only wish that the Cutting Height was on both sides. But I guess, now that I mention it, I could do that myself.

 

DSC07974.thumb.JPG.16d4f19461f998a4e34ee869e750332c.JPG

 

DSC07978.thumb.JPG.bd9ed419d039af8104ac7d35e2fcfb4e.JPG

 

 

:text-yeahthat:

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Lee1977
1 hour ago, scoob8000 said:

Ed,  They are a mulching/discharge/all in one type blade.   They look like a standard hi lift blade, but with cutting/mulching edges on the lift "wing".  

 

Last mow I stuck my old original blades back on and honestly not really any difference.   Just bigger clippings.

 

Can someone measure the rough diameter of their spindle pulleys on a 42" SD.  I don't have a model, but mine is a 1994 model.    I don't know why I never thought about it, but the spindle pulleys on my 48" are quite a bit bigger than the 42".   Maybe if they're the wrong size, they're spinning too fast?   (Grabbing at straws)

 

The larger pulley on a 48" deck is there for a slower turning blade. The blade tip speed is the same on the 42" deck but it need to turn faster to get the same tip speed.

Edited by Lee1977
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Lane Ranger

John:  I have one of those John Deere blade height adjusters and I use every spring to   start out mowing right !

 

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smoreau

Have you checked to see if the center spinal is moving on the deck?  I have seen the 42 sd decks brake the metal around were they bolt many times. They don't have the stiffing plate the 48" decks have. I have prepared 3 of these decks for this issue in the past. Grass rots the metal around the spindle and makes a week spot. Then the deck cracks around the spinal and you can get scalp marks in the grass. Ebay sells weld plates for this issue. 

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scoob8000

Shallowwater,   That's a handy tool.  I just ordered one.   Way easier than my block of wood or TP tubes.   :)

 

Smoreau,   This 42" deck is very solid, and damned near mint condition.   I've replaced all the bearings in the spindles and didn't notice any cracks.

My 48" on the other hand from the parts mower was a mess.   I spent hours welding on it to get it right.  It's solid now, but trying to keep some use off of it since I know those repairs I made won't last forever.

 

I start one of these threads every year in the hopes of finding something new that I missed.    I hate to throw more money on it, but I think my next step is going to be new rollers on the front and replace some of the adjusting linkage parts.

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oliver2-44

Have you checked the atachamatic on the tractor for wear.  I realize if it's worn one would think the 48" would also have problems.  Just a thout of another item to check off the list

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bmsgaffer

I will put money on the gator blades being the problem. I have had a big run around with them and here is the scoop. People will argue with me on this, and you will have varying levels of success on different decks, but here is what I have learned. 

 

The gator blades work amazingly well on any machine that is intended to mulch (our standard SD decks are not). If you put them on a discharge deck, they will severely disappoint. The reason is that those "tails" that are cut into it lower the volume of air that is moved by the blade and also makes it more turbulent. This is good for mulching decks because it lets the grass drop back down into the blade and be cut again before dumping. Side discharge decks don't have tight baffles to make sure this happens correctly. Your deck doesn't have enough airflow to keep the grass suspended in the 'jet stream' that is exiting out the chute so it drops and blows out from under the front (the path of least resistance since you are cutting high)

 

Same thing with worn blades. Many people dont realize that your blades wing-tips wear down too over time and will perform worse and worse as the airflow drops. 

 

See my terrible diagrams below. Green on the left side is air/grass flow and compares mulching deck to our decks. RIght side shows a side view of our decks with the green grass clippings and purple is what happens when there is low airflow. Also not shown well in that picture is that the purple direction will only happen with the front edge of the deck is higher off the grass, if you used the mulching blades and kept your cut down low, the grass itself would act as a baffle and the blow-out would occur much less.  

 

58f77aa374133_2017-04-1910_55_07.thumb.jpg.2a50cc2ebad06ef3f5fa88e46b704ad9.jpg

 

I learned all this the hard way on both a WH deck and a professional walk behind unit that I have. 

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Ed Kennell

                                                         :text-yeahthat:    Good explanation Brandon.    I have never used mulching blades, but it surely seems logical. 

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