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Discussion Starter · #1 ·
I'm not sure what to make of this, but I wish I could cut faster.
I have a BX2660 with the mid-mount belly mower. When I cut the grass, if I go very fast at all it leaves kind-of a line of partially cut grass; sometimes two lines. My speed is in low gear with the pedal depressed about a third of the way and engine at about 3000 rpm. My guess would about 3 mph, or a moderate walking speed. Does this sound normal? This machine has less than 30 hours on it but it did the same thing when brand new. Grass cutting is it's major function in life. Oh, and the same thing happens whether I'm cutting my yard and the grass is maybe 5 inches high in places, or cutting the clubhouse grass and they grass/hay is over a foot high.

Any thoughts, please?

Thanks,
David
 

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Are you cutting with WOT? The faster the blade turns the better the cut.
 

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Something is not right..

I have an 1850 w/ 54" mmm and mow in low range at about 2700-2800 RPM. The accelerator is fully depressed unless I go through some really thick grass. My cut is really nice and I'm not trying to be picky by going slow. I read on here that blade tip speed is important so I keep the RPM's up but they are not as fast as yours so something must be askew. Sounds like a dealer issue to me. Let them figure it out. (I'll bet somebody here knows what's wrong. This bunch is amazing.)
 

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David, I usually cut in high gear and go as fast as the terrain allows and generaly get good results so I feel safe in saying theres no inherent problem w/a BX MMM.
My BX23 doesn't have a tach so I don't know the exact rpm I"m running but when mowing I set the throttle just a hair or so under WOT which I'd guess to be around 3000 rpm.
I also run regular lift gatorblades and will probably go to the high lift versions for next season. Course I've said that for the last 2 or 3 seasons but these gators just don't wear out :D I do feel that the cut would be better w/the hi-lifts and I think the type of blade you're using "may" be part of the problem.
When I'm mowing the small patches of bermuda grass I've got to go slower to get a good cut and when I mow the front which is mostly fescue I don't go as fast but this is mainly because of all the obstacles I've got to mow around.
The back field is where I lay the speed down and it does pretty good, good enough.
I generally mow @ 3" but will go up to 4" if we're in a drought or it's grown too fast.
My swags for you are 3 fold.
1) if you're running the OEM reg lift blades you should try either the OEM hi-lifts or go w/a set of hi-lift gators, either of which will outperform the OEM reg lifts.

2) make sure your MMM is setup right. Make sure the side to side is within 1/16" and the front should be 1/8" lower than the rear. Make sure you measure at the blade tips and not the deck itself.

3) Adjust your speed to the conditions and grass type. What type of grass are you mowing? If it's thick like bermuda going slow is about the only way to mow it to get a good cut. If it's a fescue type you can hammer down.

I'm no expert but I get a real nice cut out of my BX23 w/60" MMM and I make sure my blades are sharpe and the MMM is plumb at teh 1st of the mowing season and usually don't have to mess w/it unless a scheduled maintenance comes up during the mowing season and I go over it again.
Good luck
Dave


a couple thoughts
 

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Re: Something is not right..

I have an 1850 w/ 54" mmm...
Now there's an apples to oranges comparison. Maybe he could trade his in for an 1850.

There are a lot of variables to consider in just how fast one can cut. Lots of people report issues with cut quality at higher ground speeds. Running the blades at max RPM can help. Leveling the deck might help. Choosing a higher cut height can help. Different blades might help. Cutting more often so you're not cutting as much in one pass can help.
 

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Discussion Starter · #6 ·
My original post says my rpm and estimated speed in mph. I don't know why everyone asked again.
Dave, I don't quite understand where one takes the measurements to which you refer. My rig is all factory and the 60" deck is supposedly self-leveling.
I started out with 2 1/2" cut and that left the yard much too bare. After one season of experimenting, I now have the roller wheels at 3 1/2" and the deck set at 3 1/2", as per the manual.
Sorry, I don't know which grass type is what.
 

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With my 2660 I cut my yard at 2800-2900 rpm and height set at 3", when cutting the field grass I go to 3000 rpm and height set at 4". I mow in high range, generally at about 1/2 to 2/3 of max speed out of the HST. I have not experienced the type of issue you are having, and I am all at dealer settings. I do note that when cutting long grass/wildflowers in the field in spring, that the front wheel on the un-mowed side depresses the grass enough that some is missed and springs back up later.
 

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David, if you have the MMM's owners manual; it covers how to adjust it. If not heres a quick instruction.

1) Assuming the stop adjustment is correct when the MMM is at the Top position, set the depth wheel to the most common setting you mow at then lower the MMM to that position.

2) You'll need a gauge for this step, I made a 1" - 4" gauge out of cardboard. Cut a piece of cardboard approx 2": wide and 4" tall and put marks on each edge in 1/2" increments. I used a red sharpie so I can see it easier.
On the outlet side of the MMM, spin the blades until the outside blade tip is pointing straight out (side to side), measure from the flat ground to the bottom of the blade tip, write it down or memorize it. Now go to the other side, spin the blade until the tip is pointing striaght out (side to side) and measure from the flat gorund to the bottom of the blade tip. If it's not with 1/16" of the other side your MMM isn't plumb side to side and you'll need to adjust the lift link adjustment. Basically you want them to be as close to exact as possible but 1/16" difference isn't too bad.

3) with the side to side plumb you'll now want to check/adjust the front to back.
Starting at the outlet side, spin the blade so it's pointing front to back then measure the front blade tip to ground then measure the rear blade tip to ground. The front should be 1/8" to 1/4" lower than the back. It should also be "at" or very near the measurement you had on the side to side.
Now do the same measurement on the other side blade.
If they are off, you adjust the nut's on the front MMM attachment link to bring them into correct measurement. Turning the nuts in will raise the front of the MMM while loosening the nut(s) will lower the front. Keep in mind that you want to do both nuts the same amount of turns.

Once set they usually will maintain the adjustment for yrs or until you slam the MMM into something :D

I've seen some fancy blade tip measureing tools around. I know JD makes one and I believe I saw another at a SCAG dealer. My piece of cardboard tain't fancy but it works :D
Another idea is to use a piece of 2x4. I believe it can be used to set the blade tip heigth from 3-3/4" to 4".

One other thing. The anti-scalp wheels shouldn't make contact w/the ground "unless" they encounter a momentary raise or fall in the terrain. They aren't gauge wheels, they are anti-scalp wheels. My manual calls for them to be approx 1/8" off the ground at the MMM mowing setting but I generally run mine one notch higher so as to minimize ground contact. I have found that they take less of a beating when they're set alittle higher and I see no difference in the finish cut. Course I've eliminated all the possible ruts and hills so blade scalping isn't a problem on the 4 acres I finish mow.
Good luck
Dave
 

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I have the same problem as Sawbuck. Sometimes, when the grass is a little longer than usual, the front tires flatten it before the deck passes over, leaving lines of longer grass when it pops back up. The longer the grass, the more it happens. So your deck and blades may not be at fault. :)
 

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My guess is that David is seeing a missed strip in between the blades and not under the front tire. When cutting certain grasses in certain conditions, the cuttings don't clear out fast enough and the build-up pushes down the uncut grass, getting missed by the blade. As said, there are many factors. It could also be a build-up of cuttings stuck to the underside of the deck preventing the clippings from clearing.
 

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My guess is that David is seeing a missed strip in between the blades and not under the front tire. When cutting certain grasses in certain conditions, the cuttings don't clear out fast enough and the build-up pushes down the uncut grass, getting missed by the blade. As said, there are many factors. It could also be a build-up of cuttings stuck to the underside of the deck preventing the clippings from clearing.
That pretty much sums up my problem. I let my grass get too high when it was raining every other day in June, and the grass clippings clogged my deck up, causing me to miss a strip.
 

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Discussion Starter · #12 ·
Y'all may have hit it. Grass under the wheel areas are not the problem, it's always strips down the "middle." Usually on the left side about 1/3rd the way in, but sometimes it is the right hand side, also about 1/3rd the way in.
 

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I noticed recently that I was not getting a level cut on slopes especially on the uphill side so I checked the plumb of the blades as Dave suggested. Sure enough there was about 1/2 inch difference between the two sides and I adjusted the links. I cut at 2 inches @ 2900 rpm (centipede grass), generally in high range. Now the mower is cutting very even. Just one question Dave, how in the world do you easily check the blade opposite the mower chute? I had a heck of a time getting my fat hands under the deck to check that blade!
 
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