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Hydro lurching, not smooth


SimpleAlex

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Me again.

7116H

Now that it's not freezing out, I've been getting things cleaned up a bit. I sprayed the hydro pump down with degreaser to clean he fins off and took it for a little dry-out ride around the yard.

I noticed that the hydro seems very jerky, as in, the arm moves smoothly but the tractor seems to lurch faster at several points in the travel.

I don't recall this happening while I was blowing snow this winter, but there was a lot going on so it's possible I missed it.

Any ideas what might be going on, or is that normal?

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Two things well make that three things come to mind, first make sure your belt isn't slipping due to a) being wet or b) the idler is hanging up not allowing full spring tension on the belt. The other item (s) to check are the bolts on the side plates, make sure they are all tight, as that can cause issues. Last of course is to check your fluid level and well that's four things to check.

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Along with the side plate bolts, check the 4 in the front of the bevel gear transmission, to frame. Your 7116H is easy to access due to the frame being open on the bottom.

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quote:Originally posted by JimDk

Along with the side plate bolts, check the 4 in the front of the bevel gear transmission, to frame. Your 7116H is easy to access due to the frame being open on the bottom.


id="quote">
id="quote">That's the first one I thought of . I understand that the BGB bolts take quite a beating using these tractors in snow removal and need to be checked annually to insure they are tight.
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Anyone able to point me to the plates/bolts to check on the parts diagrams?

The idler looks to be free, although the clutch linkage is lose and rubbing against it so I'll have to get that tightened up. It's possible that the spring on the pulley is bottoming out, so to speak. There's not much room for it to collapse any farther than it is, and there doesn't seem to be any way to adjust it other than getting a new belt.

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There are three holes in the idler bracket. That the idler pulley mounts to. Not sure which one yours is in, but you may be able to move the pulley into one of the other holes. Make sure that the idler bracket is moving freely. There is a bushing inside the bracket and the bushing will sometimes rust itself to the idler bracket.

Jim, has some good advice and in the Tech Tips forum there are instructions on how to adjust the hydro.

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Checked the idler arm, and it moves just fine.

It seems to be hitting a piece of the cowling/screen that goes over the hydro cooling fan, though. The pulley is on the highest up hole on the arm, so I can't get it any more room.

Does that mean the belt needs to be replaced? I can't see any other way to tighten things up so the arm doesn't come up so far and hit the cowling.

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If you replace the belt it is 1/2" X 46" or Simplicity part number 1650502.It shouldn`t hit the fan cover. Who knows what the PO put on it for a belt.

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If the 6 bolts that hold the bevel gear box into the tractor frame get loose, as the terrain under the tractor changes during movement it will flex the tractor in the middle and end up intermittently pulling on and relaxing the hydro control rod thus making your tractor hydro seem choppy and speed up/slow down.

It is a common thing for these 6 bolts , 3 on either side of the frame at the gear box to loosen over time or after being improperly tightened.

Check them..in addition to seeing if the belt is actually the correct size

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I checked everything out, and it all looked good. Fluid was full, BGB bolts were all tight.

I picked up a new belt and changed it out. The new belt was a TON tighter than the one on there. I had to move the idler pulley down a notch to give the linkage a little room. That seems to have solved the problem for the most part.

Still seems a little more of a step function than a smooth acceleration and deceleration, but much better.

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I took the spring on the hydro linkage off to try and get the hydro arm to move easier, and, lo and behold, the lurching has gone away too. Smooth as can be.

I'm going to put a smaller spring on there to take up a little of the play, but it certainly doesn't lurch any more.

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  • 1 month later...

I may have spoke too soon.

Now that I'm out mowing regularly, the lurching/jumping is driving me crazy. It's the worst right around the neutral position. So that first little bit of acceleration in either direction from stop.

BGB bolts are tight, BGB fluid is filled, hydro fluid is full, new hydro belt, lubed the whole linkage, and replaced the small spring on the cam.

It's almost as if the travel on the shaft assembly that moves the hydro control link is nothing for the first little bit, then jumps too quickly. If I move the hydro arm VERY SLOWLY it seems to operate fine.

I ordered a new cam roller to see if that has anything to do with it. I suppose if it were oblong and not rolling smoothly that could account for non-smooth travel.

That cam and the hydro filter are the last remaining parts that I can think to go over.

Any other ideas?

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Remove the nut at the bottom of the handle that the linkage bolts to and make sure it isn`t egged shaped. Could be the cause. Had to change a hydro handle last year because of that.

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