Tractor Shutter upon bush hog start up

[HawkinsHollow]

I use an old beat up 5' bush hog a friend gave me. When I start the PTO while the bush hog is attatched it gives a pretty good shutter that translates into the tractor. It is not an ultra violent or worrisome shutter but it is significant. Seem like that would be a normal occurrence considering 2 large metal blades are being spun up, but I wanted to make sure. Have a great day!!

 

[ptsg]

Your uses a wet clutch pack. While I do believe it has a little bit of soft start feature, at least I've noticed it on mine, it can still start things somewhat violently. Specially a bush hog with the blades folded all over the place.

 

[tacticalturnip]

You've got it throttled down when you engage the PTO, right? Assuming so, and that the shudder is what I'm familiar with, it sounds pretty normal.

 

[Slowpoke Slim]

Your uses a wet clutch pack. While I do believe it has a little bit of soft start feature, at least I've noticed it on mine, it can still start things somewhat violently. Specially a bush hog with the blades folded all over the place.

My experience also. If one or both blades are slightly folded (or fully folded) and you start the pto, yes it's going to shake pretty good for a moment while everything straightens and balances out.

I wouldn't worry about it.

And you should be starting that pto at idle (I do), or very near idle speed. Don't run the rpms up to half or full first. That's asking for trouble.

 

[ericm979]

Mine does the same thing. Also after pulling up a good size rock out of the ground and bashing it for a while before I could lift the mower, sometimes when I start it the mower vibrates and doesn't stop. I have to stop it making sure its come to a complete stop and try again.

I've inspected the mower and don't see anything obviously wrong.

And yea this is all starting at idle.

 

[Roadworthy]

Check under the mower to see if one of the blades is folded or broken. That will throw things out of balance and it will shake - a lot!! If a blade is folded and jammed you may have to extend it manually with a pry bar or something.

 

[NoTrespassing]

That's my guess, one or both of the blades isn't swung straight out causing it to be out of balance. You mention it's old and beat up, it may have a damaged blade but I would guess it's just corroded and not swinging properly.

 

[bearthebruce]

sometimes when I start it the mower vibrates and doesn't stop.

When that happens on my brush hog, I shut down, and inspect the blades. They should freely spin. If they do not, they may be locked in an abnormal location which induces a force that is not on center when spun. That causes the vibration.

I choose to make sure the blades spin freely so they can center.

I also make sure both blades have about the same meat on them - weighing about the same. If a chunk is missing, the blades will be out of balance causing vibration.

@ericm979 being a super user, I am sure you know all this. I wrote it mainly for others like the OP.

 

[oosik]

I have two implements that run on PTO. JD 750 lawn mower and Wallenstein chipper. Sometimes my lawn mower starts the mower with a noticeable shudder. It's got electric activation and is either - all on or all off. There is no feathering. It will sometimes drag the engine down and cause it to stop. The second startup will always get the blades spinning.

I can feather the pto engagement on the tractor. From the tractor running at idle - feather the pto - get the chipper spinning - bring the tractor up to pto speed. The tractor is a MUCH MORE gentile system of engagement.

 

[manac]

“an old beat up 5' bush hog”. I bet it’s pretty loose and you’re going through a resonant frequency as it spins up. As someone also suggested you could be extending a blade that was folded. If it spins smoothly at speed your fine.