New 850

[thomasalva]

I have a couple of older tractors (Massey 35 Deluxe and Ford 8N), but just acquired an early model 850 (sn 4290). It has about 1000 hours, and everything seems to work fine so far (after refurbing the starter and a few other minor things), but I don't have an operator's manual for it.

I was testing the hydraulics last night, and it all seems to work very well (no noticeable leak down which is nice compared to my other tractors). However there's a knob centered directly under the seat which when closed (full clockwise) disables the lift. Opening it up allows the lift to work normally.

Can someone tell me what this is for? I hope to have some time this weekend to look a closer look at the control valve and plumbing, etc., but it would be nice to have a head-start.

 

[Car Doc]

You might get some more help at the Yanmar forum on this since this tractor was built by Yanmar for JD nice find btw.

 

[BRBurns]

It's the speed adjustment for the 3 point hitch. Sounds like it works:thumbsup:

 

[thomasalva]

Thanks, that makes sense. It's a neat little tractor, not as powerful as the Massey, but the diff lock is nice and it has a tight turning radius. I got it for a song and had planned to clean it up a little and sell it, but I don't know now. I have five acres and run a 5-foot tiller, so I need to find out if it'll handle that. The clutch was stuck and one of the brakes was also stuck engaged, but I've freed it up and other than piddly stuff like minor electrical issues (headlights, turn signals, etc.) and needing a new seat, it's actually pretty clean.

It has turf tires and it came with a 7-foot JD flail mower, a JD 550 tiller (4 foot I think), a 6 foot Howse brush hog, and a small box blade. I may end up keeping the tractor (especially since I think my wife could handle it) but I'll probably sell the tiller, box blade, and brush hog since I already had those implements.

 

[Car Doc]

My Yanmar operators manual says its a 3pt lock and you are not supposed to operate the draft control lever when its closed.

Mine doesn't work for that so I cant relate personal experiences using it but I also have extra external hydraulic hoses on my draft control valve for some reason so thats probably why mine is inop?

From my way of thinking it would be probably be used lets say for holding an attachment at a point where it wouldn't leak down or some other reason I cant think of rather than a speed adjustment as was mentioned.

Mine has the optional auto draft control and there is a speed (sensitivity) adjustment but the knob would not be a good idea for that since its in the pressure circuit w/o relief IMHO.

 

[RoyJackson]

All the Deere CUTs have that "Rate of Drop" knob... don't know if Yanmars have it, but the Deere designed tractors built by Yanmar do...as does my 4400 which was built in the US (has a Yanmar engine though).

I don't like my implements dropping too fast, so that knob is handy to slow the descent. The only time I close it entirely is if I'm transporting an implement any distance (very rare in my case but some folks do) or if I'm working under a raised implement (definitely use jackstands too!!!).

 

[Ductape]

Feel free to post a few pictures of your new tractor if you can ! :thumbsup:

 

[Car Doc]

Yeah I have to agree with everybody on the rate of drop knob now I read up on it.

I believe Yanmars is the same they dont describe it as such but a read between the lines says it will surely work the same. :thumbsup: