Bad Vibrations

[adsm08 1,434]

So while mowing tonight the 855 suddenly got a nasty vibration. When I bought it it seemed pretty smooth, especially for an old tractor, a month or so ago it started with a little vibration, nothing worrisome, and really only felt in the foot rests. Tonight while I was mowing it got worse all of a sudden. I still only feel it in the foot rests, but now it is like standing on one of those shiatsu massage machines. At first, when it started I stopped and checked the oil, which was a bit low, so I topped it up, and the vibration went away for a while, but came back.

 

Any ideas where I should start looking? I'm going to bring my timing light home tomorrow and check that.

[lynnmor 6,777]

Start by eliminating the mower deck.

[adsm08 1,434]

42 minutes ago, lynnmor said:

Start by eliminating the mower deck.

 

Forgot, did that. When I shut the PTO off the vibration does not change. In gear or out of gear, moving or sitting still don't seem to matter either.

 

Throttle seems to make the biggest difference, but doesn't eliminate it.

[ZXT 2,394]

Loose engine mounting bolts?

[troutbum70 857]

I would agree on the loose engine mounting bolts or a couple broken ones. Does that engine sit on rubber? 

[SylvanLakeWH 24,130]

9 hours ago, ZXT said:

Loose engine mounting bolts?

 

 to start. Then go around tractor tightening bolts as you go...

 

Any sheet metal humming? I had the foot rest bolt loosen up on me and the vibration was amazing...

[lynnmor 6,777]

Loose flywheel?  Broken magnets in flywheel?

 

[Lee1977 6,217]

I would check the drive belt for a piece missing or loose pulleys. It could also be a bad bearing on the input shaft of the transmission.

[stevasaurus 22,230]

No, no rubber under engine mount.  

   You just have vibration...no strange noises??

[adsm08 1,434]

I got to checking it here a few minutes ago. Like Stevasaurus said, no rubber, my block/pan is bolted right to the frame. I did grab the engine and shook it, which rocked the whole tractor, and helped me notice the large bolts that hold the drive belt guard to the engine was gone, and letting the guard flop and ride on the back side of the belt. 

 

I fixed that and ran it for a few minutes, it was nice and smooth like I remember it being, but I didn't run it real long, so I guess time will tell.

[stevasaurus 22,230]

I think you found it!!  Wouldn't hurt to just look it all over to see if anything else has worked loose.  Nice that this was a simple fix.  

[adsm08 1,434]

2 hours ago, stevasaurus said:

I think you found it!!  Wouldn't hurt to just look it all over to see if anything else has worked loose.  Nice that this was a simple fix.  

 

I hope so. I'm going to give it a more thorough look-over before I use it again, but I'm down to only mowing about once every other week, so it may be a bit.

[adsm08 1,434]

Well fixing the belt guard made it much better, but did not fix it altogether. It has been tolerable, so I haven't been worrying about it much.

 

Today while mowing the PTO tension spring fell off the tractor. The cotter pin that holds the spring to the pedal arm tore. While fixing that I noticed a crack in the frame rail just about even with the PTO pedal. After cleaning it up I found the spot has been welded previously as there is a bead already there.

 

I'm gonna have to tear into it pretty good to be sure, or even to get at it to fix it. In the mean time I think my dad has a spare 32 or 36 inch deck and mule drive for his 310-8 that I am going to try to rig up to the 800S. I'm told it can be done. The guy I bought the 800 from hinted at, without coming right out and saying that he had this tractor in that configuration at some point in the past.