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Tractor Vibration


bkent's Avatar
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05-08-03, 03:53 PM   #1  
bkent
Tractor wants to shake me off...

I have a Yard Machines 18 hp, 42" deck mower. Couple weekends ago while mowing I hit a big rock. The deck would rattle when I engaged the drive belt, and I thought I broke the pulley on the right blade.

I ordered the new part and it came in yesterday. I pulled the deck off, and discovered that the bolt that held the right blade was just loose. I tightened it up, then changed the oil and air filter/pre filter. I backed it outta the garage last night and fired it up. Started and idled perfect. Then I engaged the blades and they sounded normal.

I came home from work today to mow, and when I engaged the blades/deck it started rattling real bad. I pulled into the garage, shut her off and took a look at the deck. The blade(s) seemed to turn fine, they didn't hit the deck anywhere. I tried it again and got the same rattling result.

What could be wrong? If the blade(s) are unbalanced wouldn't it have rattled last night? I re-installed the deck correctly, double checked the stabalizer plate and everything.

Any advice?

on a side note the blades are pretty beat up, the previous owner has 10 acres with 3-4 finish mowed. If it is the blades how much (ballpark) would new ones cost? (2 blades for 42" deck)

Thanks.

 
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05-08-03, 10:10 PM   #2  
Hello bkent!

Grab one end of the blade and try to wiggle it up and down. Watch the pulley to see if it moves much. If it moves up and down, you need mandrel assemblies. If not, on to next thing. Rotate the blade and watch the clearance between it and the front of the deck. If there is not a good 1/2" clearance, your deck needs to be bent away from the blade. (It can hit the deck when turning at high RPM, but clear the deck when turning by hand). Also check to be sure there isn't a chunk missing off of your belt, or a thin burned spot on it. This will also cause a vibration.

Post back and let us know what you find!

Oh...blades should run $10 to $12 a piece.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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05-09-03, 05:46 AM   #3  
bkent
the Blade was actually touching a spot on the "lip" of the open end of the deck (that spits grass out) when I spun it by hand. I solved this by pounding that part of the deck out so it didn't touch when spun by hand. Do I need 1/2" of clearance all the way around?

The other thing I noticed when I had the blade off, is it possible that I sheared the star pattern on the blade that centers it on the bolt? That could explain why it worked 2 nights ago, but was off this last night...

I really need new blades anyways as the existing ones are beyond just needing a sharpening. I think I'll just get 2 new blades and see if that resolves it.

 
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05-10-03, 01:37 AM   #4  
Yes, it is possible that you sheared the star off of the jackshaft. If so, I would replace it. 1/2" is not necessarily required, but you should have close to it. If your bearings are tight, 1/4" should be fine.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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