Grass isn't cut between the blades.

SGray

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Is there a way to fix the problem of grass left uncut between the blades? It is particularly bad between the left and center blade. I removed the relatively new blades (installed about 2 months ago), and rotated them, L to C, C to R, R to L, and I get the same result...2 stripes of grass the entire length of my mowing, which means I have to mow over the same path a second time, but slightly moved to the side to make sure my blades cut the 2 stripes that are left between the 3 blades. The grass between the left and center blade is up to 12" wide, while the grass left between the center and right blades is about 2-4" wide. I have the ProMaster 260.
 

ILENGINE

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Is the grass not being cut at all on those strips, or is it being cut but not the same height as the outside blades.
 

Rivets

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When did this start occurring? All of a sudden or over time? Did you do any maintenance just before the problem showed up? Have you leveled the deck? If you are skipping that wide of a strip, I would be checking to see if all blades are turning at the same speed. Have you checked to see if your belt is worn, all spindles are turning freely, belt tension is correct, and all pulleys are in good condition.
 

SGray

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It has done this since I purchased the mower about 15 years ago. I purchased it used with about 100 hours on it. I took it to a Gravely dealer and told them about the two stripes. I asked if a new mower would leave the stripes. The dealer said, "no". I left it with him and told him to do what needed to be done to make it cut like a new mower that doesn't leave the stripes. He had it for about a month waiting on a part. When I got it, he said it's like new. I asked him to come with me to the side of his business where the grass was tall, like I typically cut when mowing. I ran the mower through the tall grass and it left 2 stripes. The dealer told me he had done all he could do. It's been that way ever since, but the stripes have typically been no more than 2-4" wide in tall grass/weeds, but it cuts OK without too visible of lines when mowing in the nice zoysia grass around my house. Now when cutting weeds, the left cutting side stripe is about 12" wide. I've looked at the blades under the deck. There is a visible space between the blades...probably 3/4", I'll guess. See attached photo. I will put a new blade belt on it tomorrow to see if that helps. One more thing...it doesn't matter if I drive slow or fast. The 12" path of taller grass left between the left and center blades is still there.
 

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SGray

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I haven't checked all of these things lately. I'm mowing a pasture right now that isn't mine. When I finish it, I'll bring the mower home and check all of this. How do I check for blades turning at the same speed? I've thought of this, and wondered if maybe the taller grass/weed is making the left blade turn slower, as if the belt is slipping around the pulley. I'll install a new blade belt before I mow tomorrow. Right now, my mower is sitting in a field with a broken PTO belt. I just purchased a new PTO belt this morning and I have a new blade belt in my shed. I'll install both belts tomorrow when I go back to finish mowing the pasture.
 

StarTech

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A common problem when grass to is too tall. Grass is laying down as mow the blade are not creating enough suction to raise the grass back up as blades are passing over it.

If you have notched style changing to none notched hi lift blades might solve the problem.
Notched blade
1716659869304.png
None Notched blade. Larger air lifts
1716659913888.png
 

SGray

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I don't think your new blades are as long as the original blades.
I'll measure them tomorrow. I have a 60" mower, so I assume the blades should be around 20" each. I remember reading that the Cub Cadet Tank mower has overlapping blades and the pulleys and belts have teeth so that the blades are positioned at 90 degrees to each other when the belt is installed so the blades won't hit each other when turning. The teeth in the belt and pulleys prevent the belt from slipping as you don't want the blades to hit each other. The overlapping blades keep the striping from happening. Yep, I just found it online. The 60" mowing deck uses three 21" blades. That's 63" of blades for a 60" deck. Maybe Gravely should consider this design.
 

SGray

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A common problem when grass to is too tall. Grass is laying down as mow the blade are not creating enough suction to raise the grass back up as blades are passing over it.

If you have notched style changing to none notched hi lift blades might solve the problem.
Notched blade
View attachment 68731
None Notched blade. Larger air lifts
View attachment 68732
I use non-notched hi-lift blades.
 

GrumpyCat

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I'll measure them tomorrow. I have a 60" mower, so I assume the blades should be around 20" each. I remember reading that the Cub Cadet Tank mower has overlapping blades and the pulleys and belts have teeth so that the blades are positioned at 90 degrees to each other when the belt is installed so the blades won't hit each other when turning. The teeth in the belt and pulleys prevent the belt from slipping as you don't want the blades to hit each other. The overlapping blades keep the striping from happening. Yep, I just found it online. The 60" mowing deck uses three 21" blades. That's 63" of blades for a 60" deck. Maybe Gravely should consider this design.
Wasn’t thinking your stripe was so wide.

Your center blade is in front of the side blades, the cut overlaps but the blades can never hit each other. An uncut stripe can be produced cutting during a tight turn,

Am agreeing with others your center blade is slipping on the belt, or pulley slipping on spindle.
 
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