Mower Deck Vibration

TORQUIN · Jul 8, 2004

I have a Scott's (Made by JD) 46" riding mower with 3 blades. When I engage the blades I get a vibration. It's more thanm normal, but is not so bad I can't cut grass with it. I tried to make sure the blades were balanced last time I sharpened them. I also greased the blade shafts when I sharpened the blades this Spring. I can't think of a way to spin up each blade separately.

Anyone have any suggestions on a safe way to determine what the vibration is?

Thanks,
Chris

yellowsocks93 · Jul 8, 2004

If you take off the mower belt you can spin each individually. Is there anything wrapped around the blades? Also try cleaning the bottom of the mower deck. As grass builds up, your blades will begin to hit it then your blades will be junk and you will be burning belts.

GerardC · Jul 9, 2004

Did you hit something? Possible bent shaft?? G

Gatorboy · Jul 9, 2004

Did you hit something? Possible bent shaft?? 

Or, if you did hit something and your blade happened to get bent, this could cause a vibration as well.

Ledgemere Farm · Jul 9, 2004

Or, as in my case, bent blade and bent shaft /forums/images/graemlins/tongue.gif

SPIKER · Jul 9, 2004

Also look to make sure that all the blades are mounted tightly, and CENTERED on the bolt/shaft. yes there is a lip/bead that helps hold the blade centered, but you acn install a blade OVER the lip/bead rather than ON it which will then set the blade off center. that s what happened to my murry, which was maybe my fault I installed blades tightly but left the deck ON and I was working under the mower blind and by feel. yep that is what happenes when you get in a hurry.

blade ballancers can be had cheap just look like the OLD bubble ballancers for auto tires only on a small scale. just set them on it and grind the low side so that it sets even/level across, don't forget to look at the blade from the end front to back not just side to side.

Mark M

TORQUIN · Jul 9, 2004

I won't say I couldn't have one of the problems you describe, since I live in a virtual rock quarry. /forums/images/graemlins/crazy.gif
Every time I think I have gotten all of the rocks out of the yard, there's ANOTHER one. Wish I could find the rock- magnet switch on that mower so I can turn it off.

I don't figure I will be able to turn the blades/pulleys by hand fast enough to tell about the vibration, unless something is noticably bent.

I usually tighten the blade by hand, slowly until I can feel it is seated on the shoulder properly, so I can be sure the blade is centered. I will check that again though.

One thing I just though of, I could probably do, is pull 2 of the 3 blades off and fire up the mower, then swap blades until I get a vibe, and if I get no vibe, then move one blade from shaft to shaft until I get a vibe. That might do the trick, and should be safe to do. What do you think?

Thanks,
Chris

antg · Jul 14, 2004

Almost every time I've had a vibration from the mower deck, the problem was traced to the drive belt. Check your belt for a flatten spot or any variation in the belt such as a spot where the "V" cross section is not uniform along the length.

JimR · Jul 14, 2004

Take off all but one blade and try it till you find the problem blade.

TORQUIN · Jul 14, 2004

( Almost every time I've had a vibration from the mower deck, the problem was traced to the drive belt. Check your belt for a flatten spot or any variation in the belt such as a spot where the "V" cross section is not uniform along the length.
)

You may have just hit on a solution! I do have a flaky belt on there. I bent a pulley a while back and cut the belt, after straightening the pulley and replacing the hard-to-find belt, the darn thing cut into the belt again, but not much, so I am just careful about engaging the blades. I guess I will look into getting another belt now.

Thanks,
Chris