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Mower not cutting all the grass


Dixie2012's Avatar
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03-28-18, 04:41 PM   #1  
Mower not cutting all the grass

Last year, I noticed that my Husqvarna 46" mower wasn't cutting all the grass. With every pass, there was one "sprig" of grass sticking up by it self. All the other grass was cut except one "sprig" just standing there alone.
Now its never where the front tire ran over it & mashed it down. Its usually near or about the center of the deck.
After a couple of mowings, I decided the blades needed to be changed so I put two brand new blades on it. Same thing. No difference.
This year, same thing. It could be a little worse. Leaving behind a few more "sprigs" of grass just standing there alone. I am wondering if the spindle might need changing. The belts are not squealing or slipping, burned or worn. They don't appear to be loose like they are stretched. I wonder if the spindles are worn out where the belt & pully's are at the correct RPM, but those RPMs aren't the same at the blade. If the spindle is worn out & slipping...???

Now, don't get too caught up on that. Its just a thought on my part. What do you think it is?
Belt? Pully? Spindle? Bearing? Just trying to mow to fast?
I have 5 acres so I am "hammer down" when I mow... but I always have been "hammer down" when mowing unless the grass was over grown a bit & it wasn't cutting the grass over all. But this is a few sprigs here & there that doesn't seem to have been touched at all. And again, it aint in line with where the tire has run over it & bent it over until I passed.

 
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03-28-18, 05:00 PM   #2  
Blade spindles are offset on the deck to provide cut overlap without interference. If the deck is moving at a right angle to a line through the spindles some grass could be uncut especially if the blade RPM and the forward speed are not a good match. Try a slower forward speed without changing engine RPM.

 
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03-28-18, 11:40 PM   #3  
Make sure you are mowing with the engine at full speed and make sure the blade lifts are good and pointing up, not down.


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03-28-18, 11:58 PM   #4  
have 5 acres so I am "hammer down" when I mow
Probably over all travel speed where a few "sprigs" are just getting missed.

 
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03-29-18, 03:53 AM   #5  
Since it's in the middle, I'd suspect the blades, just like Beezlebob. As the blades wear along the cutting edge, they also wear a little bit at the ends where we expect that overlap that Beezlebob described, and it's not much of an overlap, even at the beginning of the blades' life . . . . maybe less than " on a 2 blade deck, a little more on a deck with 3 blades..

As the blades age and become shorter (just ⅛" or '), that overlap ceases to exist and we get what I refer to as grass B] "mohawks"[/B] in the center of the cutting pattern.

If you ever take the deck off, turn it upside down and examine the blades. You may line them up and see that the overlap has disappeared with older worn blades . . . . and sharpening can't help. If the blades don't need replacement for some other reason, I just use them until the mohawks become intolerable.

 
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03-29-18, 04:05 AM   #6  
After a couple of mowings, I decided the blades needed to be changed so I put two brand new blades on it. Same thing. No difference.
I would think that would rule out worn blades
I don't know much about riding mowers but would think it would be an alignment issue. If it's worn mandrels wouldn't they have play in them?


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03-29-18, 05:57 AM   #7  
If the blades are "staggered" or slightly offset from each other, the cutting paths of the blades should overlap when traveling in a straight line, but may miss a few sprigs when turning.

 
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03-30-18, 06:56 PM   #8  
I'm still working on this issue. We mowed today & it seems to be worse. I hate to say it but I am still stuck on this spindle idea. So, I got to wondering about the RPMs of the engine then the RPMs of the spindles at the blades. I have one of those handheld RPM meters. Its kinda like a speedometer. So, I put the "tach" (for lack of proper name of this thing), on the flywheel & its showing:
3050 - 3100 RPMs at full throttle. Can anyone tell me if this is correct?
Its a Kohler Courage 20 single cylinder
Product #: 100107B001297

I checked google but I couldnt find specs on RPMs.

If this is correct, then I know the engine is doing its job.

Next, I want to remove the blades & check the RPMs on the spindle. Obviously, I need to know what the RPMs on the spindle is supposed to be.... if anyone can come up with that number for me.

I did attempt to turn the blade with my hand while the mower was off & it was very tight, belt was tight etc. So, I doubt its slipping but, I wanna check. Since they are tight, I am wondering ... just the opposite. Is the spindle(s) in a bind & not turning as free as they should.

I know, I know... I'm probably going all the way around town just to get across the street, but I just wanna check this scenario out.

 
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03-30-18, 08:33 PM   #9  
You said you changed the blades....were the stars worn off? If the star mount is worn the blades will be uneven and slip. If you don't know what I am referring to.....

This is a common problem I see and the spindle/shaft may need to be replaced if not the entire mandrel.


Just needs a bigger hammer
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03-31-18, 05:31 AM   #10  
The stars were not worn that I remember. I'll check that when I get under there. Good idea, thanks.

 
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