Hit something now a loud vibration

[turbofiat124]

I was mowing the other day with my 2009 Craftsmans 48" riding mower. Its made by Husqvarna. I hit a tree branch or something while mowing my aunt's property that was buried under some weeds and now there is a slight but annoying vibration coming from the deck area. Almost like one of the blades is slightly rubbing or hitting something.

I looked under the deck. The blades are not loose nor do they appear bent but are quite dull from where I have hit small tree branches this spring. The blades come close to one another. I wonder if when they are moving they might be touching one each other when they come together. Is that possible?

I also could not find anything loose or broken on top of the deck. One of the screws did fall out from one of the plastic pulley guards. I replaced it but it did not fix the problem.

Another thing I noticed was my front yard. But this was before the vibration happened. There are 4" strips about 1" higher than the rest down each pass. I may have to take a photo. Could one end of the blade be dull from hitting tree branches? However I have zoysia grass so if get's somewhat high it looks kind of funky when mowed. It also looks scalped like I had my deck too low. But I had my deck to set to the same level I always do, notch 3. But we have had a dry season so once again this type of grass looks funky when we have a drought.

I'll try to snap a photo of my front yard when I get home.

I've got mulching blades on my mower by the way.

Also if I am sitting on the mower, the support on the rear/right side of the deck is tight but on the other side I can lift up on it. This is the side with the adjustment to set the level. I think that is normal.

When I adjust the level, the deck raises like it should.

BTW, I know you are not supposed to hit small tree branches that this will dull a blade. I'm not trying to abuse my mower but the problem is I could spend all day picking up these branches. Some of them I can't even see in the grass. Anything larger like more than 2" in diameter I pick up and throw over into the pasture or woods but I have so many pine trees, they drop branches like crazy. I can't keep ahead of these tree branches!

 

[577jersey]

I was mowing the other day with my 2009 Craftsmans 48" riding mower. Its made by Husqvarna. I hit a tree branch or something while mowing my aunt's property that was buried under some weeds and now there is a slight but annoying vibration coming from the deck area. Almost like one of the blades is slightly rubbing or hitting something.

I looked under the deck. The blades are not loose nor do they appear bent but are quite dull from where I have hit small tree branches this spring. The blades come close to one another. I wonder if when they are moving they might be touching one each other when they come together. Is that possible?

I also could not find anything loose or broken on top of the deck. One of the screws did fall out from one of the plastic pulley guards. I replaced it but it did not fix the problem.

Another thing I noticed was my front yard. But this was before the vibration happened. There are 4" strips about 1" higher than the rest down each pass. I may have to take a photo. Could one end of the blade be dull from hitting tree branches? However I have zoysia grass so if get's somewhat high it looks kind of funky when mowed. It also looks scalped like I had my deck too low. But I had my deck to set to the same level I always do, notch 3. But we have had a dry season so once again this type of grass looks funky when we have a drought.

I'll try to snap a photo of my front yard when I get home.

I've got mulching blades on my mower by the way.

Also if I am sitting on the mower, the support on the rear/right side of the deck is tight but on the other side I can lift up on it. This is the side with the adjustment to set the level. I think that is normal.

When I adjust the level, the deck raises like it should.

BTW, I know you are not supposed to hit small tree branches that this will dull a blade. I'm not trying to abuse my mower but the problem is I could spend all day picking up these branches. Some of them I can't even see in the grass. Anything larger like more than 2" in diameter I pick up and throw over into the pasture or woods but I have so many pine trees, they drop branches like crazy. I can't keep ahead of these tree branches!

You need to remove the blades and lay them on a flat surface,,make sure they are not bent,,I would also have them balanced and sharpened if not bent...could have also bent a spindle shaft if the blades are ok?
BTW-I run over small branches all the time,,A good quality hardened sharp blade will not wear much from a wooden branch,,its like a chipper/shredder..lol

 

[bertsmobile1]

:welcome:

Take the belt off
jack up the mower , put it on ramps whatever just so you can get under it.

I am guessing you have a 2 blade deck.
line the baldes up so they are almost touching.
The blades should be at exactly the same height,
Then rotate each blade 1/2 turn & check again.
Then each balde 1/2 turn one a a time.
If the height variation between the bades changes then the blade or spindle is bent.

Pull the deck out and inspect the 3 lugs that bolt the spindle to the deck.
These crack very easily and must be replaced in cracked.
Look closely ay the end edge of the blades.
If they are hitting there will be a shinny mark as they glance each other.

I have the luxury of having 97 different new blades at my fingertips so if in douby I can take a blade off and stack it on a new one to check for bends & twists.
The best you will be able to do is to lay them on top of one another then swap then around.
They should sit exactly on top os each other, no gaps if they are strait.

 

[turbofiat124]

This is what my front yard with zoysia grass looked like BEFORE the vibration started:

Afterwards I said to myself, "This does not look normal". What does this cut pattern look like to you?

For some odd reason, the section to the right appears more normal. I looked at my backyard (which I always mow first) and it looks similar but it's a different type of grass.

It looks as if the deck is set too low but notice the 4" swath, 1" higher than the rest it left behind on the outer perimeter of the cut . The deck was at the same setting I always mow at "#3". The deck seems OK, seems level. The front bar that connects the deck to the frame is still there (fell off previously and was scalping the yard). Last summer I cracked one of the rear mounts at the deck and welded it back. The weld is still holding. I think that was when trying to get it in and out of my yard barn.

I wonder if perhaps I had hit something prior which weakened the spindle and when I hit that rotten log on my aunt's property, it finally gave way?

Yes it does sound like the blades are slightly hitting one another. When the mower is not running and I am moving them by hand, this does not seem to be the case, however like you said perhaps the spindle is cracked so once it's in motion, it causes the blades to hit. I did not think to grab the blade and see if I could move it up/down or side to side.

There is some confusions as to what size deck I actually have. The 48" decks are showing 3 blades but I'm pretty sure I only have 2 blades which means i should have a 46" deck. Unless the width of the deck itself is 48" but the cut is only 46". I'll have to double check on that. I feel stupid not knowing exactly what size deck I actually have considering I've had this mower for 6 years!

 

[BlazNT]

Model number would be nice for us to see what we are working on.

 

[bertsmobile1]

From the photos of the yard you definately have one blade cutting lower than the other.
I have blades up to 38" wide so your could have 2 x 24" blades.
The only reason they go to 3 blades is to shorten the length of the deck and there are 48" 2 blade decks.

 

[turbofiat124]

I have been at the beach for a week and just got around today at looking at my mowers. Just as well since we are practically in a drought here in East Tennessee so all that has grown in the past two weeks are weeds.

I rotated one of the blades and made a mark with my Sharpie on the inside of the deck then rotated the blade 180 degrees to see if the mark aligned with the other end. It did not. About 1/2" difference.

Well, looks quite obvious that the blade on the right is bent vertically and it does not lay flat. However the blade on the left does lay flat but appears bent horizontally:

I could not find anything wrong with the spindles. The bases where they bolt to the deck are not broken. I hope they are not bent. Do the spindles bend or just break?

I ordered some new blades. I guess I'll know when I get them bolted on.

 

[BlazNT]

I have been at the beach for a week and just got around today at looking at my mowers. Just as well since we are practically in a drought here in East Tennessee so all that has grown in the past two weeks are weeds.

I rotated one of the blades and made a mark with my Sharpie on the inside of the deck then rotated the blade 180 degrees to see if the mark aligned with the other end. It did not. About 1/2" difference.

Well, looks quite obvious that the blade on the right is bent vertically and it does not lay flat. However the blade on the left does lay flat but appears bent horizontally:

I could not find anything wrong with the spindles. The bases where they bolt to the deck are not broken. I hope they are not bent. Do the spindles bend or just break?

I ordered some new blades. I guess I'll know when I get them bolted on.

The spindle can bend but the blade normally does first.

 

[bertsmobile1]

The spindle themselves bend, slip the nuts back on the end and spin them to check for eccentric rotation of the nut.
Most often the housing cracks or breaks, check them very carefully because if you fit new blades to cracked spindles, they won't be new for long.