Bushhog Vibration

[woodchuckie]

After reading this thread I realize what happens to my bush hog and why what I do stops the shaking. When I hit something big enough to fold one of my blades, it shakes until I dislodge whatever it is by raising or lowering or by moving forward or backward. It happens often because most of what I cut is 1 inch and bigger trees.

 

[Theowegian]

Actually, it is probably NOT one of the blades folding up, at least on the newer Squealers.

You can prove this by letting the tractor/mower keep running in a high vibe condition, then gently throttle down, and then shutting off the tractor. If your mower is high enough off the ground, perhaps a foot or so, you can look under the mower and see that the blades don't fold up. (Obviously, the tractor and mower is completely stopped when you peer underneath and put a concrete block under it or use a mirror).

However, if you mark the PTO / slip clutch as I described in an earlier post, you can verify that the high vibes will typically occur when the slip clutch is in a certain "number to dot" orientation.

You folks that say "...the blade is folded up", do you have a shear pin or a slip clutch drive on your mowers?

I had a shear pin mower once and I never got an intermittant vibration, like I do with my a slip clutch mower....

dwight

 

[rdam]

OK. Lot's of things to check, including the "out of sync" slip clutch theory. I'm working the weekend and will check on Monday.

Thanks

 

[woodchuckie]

Actually, it is probably NOT one of the blades folding up, at least on the newer Squealers.

You can prove this by letting the tractor/mower keep running in a high vibe condition, then gently throttle down, and then shutting off the tractor. If your mower is high enough off the ground, perhaps a foot or so, you can look under the mower and see that the blades don't fold up. (Obviously, the tractor and mower is completely stopped when you peer underneath and put a concrete block under it or use a mirror).

However, if you mark the PTO / slip clutch as I described in an earlier post, you can verify that the high vibes will typically occur when the slip clutch is in a certain "number to dot" orientation.

You folks that say "...the blade is folded up", do you have a shear pin or a slip clutch drive on your mowers?

I had a shear pin mower once and I never got an intermittant vibration, like I do with my a slip clutch mower....

dwight

Dwight
My Squealer has the slip clutch. It's a little over 3 years old. Most of that time I assumed like the owners manual said that the slip clutch was adjusted properly. Well I went about my business cutting brush and occasionaly having my tractor completly go dead due to the bush hog stopping when I hit a stump or rock. I also had the vibration at times. After all the comments about the L2800 pto I decided to adjust the clutch. It will slip now and not bog the motor at all and it still vibrates at times.

 

[Theowegian]

I can tell you that I used a pair of vernier calipers to set my clutch spring tension dimension, as the owners manual describes. (And the condition did not improve).

With all Ive said, you should consider the other possibilities, like the folded blade theory. It's just that with my Squealer, I could not verify the folded blade theory. That's why I began to look elsewhere...I can tell you that the vibe condition always appeared when I hit something hard, like a sapling or whenever I engaged the mower, even at low RPM's.

But your experience may be different than mine. I sure would like to learn more about this, if you have additional insight....Im all ears!

Let us know what you finally discover.

dwight

 

[JerryG]

You folks that say "...the blade is folded up", do you have a shear pin or a slip clutch drive on your mowers?
dwight

It doesn't matter whether it has a shear pin or a slip clutch. If when the mower is stopped, one of the blade spins back around into the stump jumper, a blade can jam there. I have seen several do that. Usually, when they start they will straighten out but sometimes they don't until the mower is stopped and restarted.

 

[Theowegian]

It doesn't matter whether it has a shear pin or a slip clutch. If when the mower is stopped, one of the blade spins back around into the stump jumper, a blade can jam there. I have seen several do that. Usually, when they start they will straighten out but sometimes they don't until the mower is stopped and restarted.

JerryG.
Thanks for your input, but I didn't know you owned a 5 ft Squealer, Bush Hog brand rotary cutter...

Ive got more than 600 hours on my Bush Hog Squealer and have NEVER have jammed a blade. Other mowers, yes, Ive jammed blades, but not my Squealer.

The original poster (rdam) specifically said the blade was NOT folded up...

I have an L3230, 8x8 shuttle with a 5 foot BushHog brand "Squealer". The BH is vibrating excessively at PTO speed, as if the blades were unbalanced. It is not consistent. It may smooth out for awhile, and after shutting down the PTO, and then re-starting a few minutes later, the vibration will be bad. All looks in order underneath. The driveshaft is attached to the PTO properly. The blades swing on the pan "relatively" easily. Cutting low, with the skids almost touching the ground, seems to smooth things out??? Prior experience with a 6 foot "Squealer" was excellent, with little if any vibration. Any ideas what to check?

So you seemed to miss my point. So I'll say it again.
If the mower is checked for a jammed blade and it is free, then the mower slip clutch can be the source of imbalance, if it has one.

dwight

 

[JerryG]

JerryG.
Thanks for your input, but I didn't know you owned a 5 ft Squealer, Bush Hog brand rotary cutter...

Ive got more than 600 hours on my Bush Hog Squealer and have NEVER have jammed a blade. Other mowers, yes, Ive jammed blades, but not my Squealer.

The original poster (rdam) specifically said the blade was NOT folded up...
dwight

It doesn't matter whether it is a Squealer or a Joe's garage model or even how many hours there is on a mower. Some mowers do it every once in a while and some never do. It seems to have more do with the length of blades relative to the diameter of the stump jumper. These lengths vary even in the same model as the size of the mower changes. Even if a blade is folded up, it may straighten out when it starts. They can also unfold when they stop but that seems to happen less often. The OP said that everything look fine when he looked under there. We don't know where the blades were before he stopped.

rdam,
Check your blade bolts to see if they are tight. If one of the nuts are a couple of threads or more lose, it will cause a vibration and can cause blade jam. It doesn’t always cause a blade jam but almost always cause vibrations. There are of course other things to check. PTO shaft: check to see if the u-joints are good, check to see if the shaft is straight, See if the PTO shaft is snug on the gear box. The last thing that I would check if every thing else is ok, is the stump jumper nut.
Good luck.

 

[jbrumberg]

I agree with JerryG. RC's should be "well balanced" at the time of purchase. It does not take much to throw one off. Jay

 

[heymack]

Also, make sure both blades are installed the same way (hanging downward). One time somebody, who shall remain nameless and was in a hurry, installed one of the blades on my bush hog "upside down." Talk about vibrations....