750 JD compact tractor

All non-Cub/Cadet/IH/Farmall/Case tractor and machinery discussions.

Moderator: Team Cub

Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.

750 JD compact tractor

Postby birddog » Wed Jan 15, 2014 6:38 pm

Anyone have any experience with the Yanmar 3 cyl. diesel that is used in these. Mine lost oil pressure. Being that it has a idiot light and not a gauge I don't know if it happened all of a sudden or if it has been gradually getting worse. I probably know all the possibilities as to what could be wrong so what I'm looking for is if there is something that may be a problem with these engines and or the most likely suspects.

I pulled the sender and tried three different manual gauges just to be sure that it was a pressure problem and not an elec. problem. Also I've pulled the pan to check the pick up tube and screen and all looks good there. There is no metal and to my surprise no gunk in the pan. Also no sign of water, my first thought was that there may have been ice some where because of the way below zero temps. we had.
Mark "birddog" Birdeau
User avatar
birddog
5+ Years
5+ Years
 
Posts: 343
Joined: Fri May 05, 2006 12:00 am
Location: WI, Catawba
Zip Code: 54515
Circle of Safety Award
Circle of Safety: Y

Re: 750 JD compact tractor

Postby staninlowerAL » Wed Jan 15, 2014 10:31 pm

I have an 850 JD with the 3 cyl Yanmar engine which I totally rebuilt from a junk engine about 10 years ago. No problem with the engine; just the oil pan was difficult to get a good seal (leaked because I couldn't keep the bolts tight. Never had any issues with the rebuilt engine (turned crank, new rods, mains bearings to fit, new pistons, reworked head, etc). This probably does not really help but that's all my experience with the Yanmar engine. (I don't like the idiot oil pressure light either, considered putting gages in but there's little room to make the conversion.)
staninlowerAL
Cub Star!!
Cub Star!!
 
Posts: 264
Joined: Fri Oct 29, 2010 11:34 pm
Zip Code: 36558

Re: 750 JD compact tractor

Postby Jackman » Thu Jan 16, 2014 6:21 am

What did the manual gauges read :?: I think your good and have electric sender issue , no oil pressure would trash that engine fast , I just sold my 850 was a good tractor 15 years good service :D
Jackman
5+ Years
5+ Years
 
Posts: 1720
Joined: Mon May 15, 2006 4:26 am
Zip Code: 000000
Circle of Safety Award
Circle of Safety: Y

Re: 750 JD compact tractor

Postby Gary Dotson » Thu Jan 16, 2014 7:09 am

The Yanmar engines are generally very reliable, I've not known of any issue specific to your problem. Maybe you could talk to a dealership mechanic, who has more experience with them.
Gary Dotson
Team Cub Mentor
Team Cub Mentor
 
Posts: 2560
Joined: Thu Aug 03, 2006 6:20 am
Location: OH West Mansfield
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety Award
Circle of Safety: Y

Re: 750 JD compact tractor

Postby birddog » Thu Jan 16, 2014 1:03 pm

Jackman;

the manual gauges read 0

There was absolutely nothing there. After the area that the sender screwed into drained, it wouldn't even pump any oil back in to the passage.

no oil pressure would trash that engine fast

That's one of the puzzels here. I thought with all the running and testing I've done there would at least be some noise from the lack of oil. The engine still starts and runs just like always, except there is no oil pressure.

I probably ran it 150' back to the garage, then 30' out into the drive, to chain it to the truck so I could tow it to the local garage, then 30' more to get into the shop, and I don't know how many times I restarted it during testing. (many times even at full throttle) Strange huh? The engine probably should have seized solid by now, but still sounds good. It's almost like the oil is going every where except to the passage where the sender screws in. I had put new oil and a filter on after it was in the shop a couple days in case it was ice. (no change) I forgot to check the new filter yesterday, to see if it filled with oil, although I doubt it, as it sits just above the sender. (I had filled it a little better then half way when I installed it)

Gary:

The Yanmar engines are generally very reliable

I agree, this has been a great little tractor with almost no problems, the only other trouble we've had is the knuckle where the steering arm attaches to the front wheel, broke. The only thing I don't like about it is the hydraulics are real slow, especially in the cold. I was told that if I could find the right mechanic that has worked on these and willing to stick his neck out, there is a way to speed them up.

Maybe you could talk to a dealership mechanic

I thought about that. The local dealer is over 40 miles away and something like that should be done in person, not on the phone. The phone might be OK if I personally new them, but I've never done any service work there, only parts. I most likely will talk to them though before taking any drastic measures.

I'll probably bite the bullet and pay the $120 plus shipping and get a service manual if I don't hit on anything else soon.
Mark "birddog" Birdeau
User avatar
birddog
5+ Years
5+ Years
 
Posts: 343
Joined: Fri May 05, 2006 12:00 am
Location: WI, Catawba
Zip Code: 54515
Circle of Safety Award
Circle of Safety: Y

Re: 750 JD compact tractor

Postby Steve Butram » Thu Jan 16, 2014 6:53 pm

you might want to check out this forum is has a lot of good information and they are very friendly

http://www.mytractorforum.com/forumdisplay.php?f=76
Co- hosting Central Indiana Cub Fest near Tipton Indiana September of 2014
User avatar
Steve Butram
Cub Pro
Cub Pro
 
Posts: 1906
Joined: Mon Feb 17, 2003 7:53 am
Location: IN West Lafayette
Zip Code: 47906
eBay ID: steveb05
Tractors Owned: 1947 in well used condition
1948 restored
1948
1949 for sale
Nice original 1950 just out of the Demo Range
628 2 wheel Trailer
1950 Demo
Circle of Safety Award
Circle of Safety: Y

Re: 750 JD compact tractor

Postby Jackman » Fri Jan 17, 2014 10:53 pm

"the manual gauges read 0

There was absolutely nothing there. After the area that the sender screwed into drained, it wouldn't even pump any oil back in to the passage.

no oil pressure would trash that engine fast

That's one of the puzzels here. I thought with all the running and testing I've done there would at least be some noise from the lack of oil. The engine still starts and runs just like always, except there is no oil pressure. "


Strange :? , I would drain the oil and give the oil a close look for foreign debris such as metal shavings and also cut open the oil filter and inspect the same, if that checks out maybe the passage to the sender is plugged ,,,,,,, veery strang no pressure yet runs :o
Jackman
5+ Years
5+ Years
 
Posts: 1720
Joined: Mon May 15, 2006 4:26 am
Zip Code: 000000
Circle of Safety Award
Circle of Safety: Y

Re: 750 JD compact tractor

Postby JackF » Sat Jan 18, 2014 7:44 am

I’m really good at doing nothing…With that said…I’m really, really good at doing nothing
JackF
10+ Years
10+ Years
 
Posts: 905
Joined: Sat Feb 15, 2003 7:20 am
Zip Code: 00000

Re: 750 JD compact tractor

Postby Gary Dotson » Sat Jan 18, 2014 7:56 am

That's an interesting link that Jack posted, maybe that's the smoking gun. I was looking at my Clymer small diesel engine manual, yesterday, to see if I could come up with any ideas for you. The pump on that engine is mounted to the front of the block, behind the front cover. It pumps immediately into the oil filter base, where the oil pressure regulator is located, then through the filter and on the the oil galleys. I would remove the filter base & check the regulator, but I'll bet Jack found your answer.
Gary Dotson
Team Cub Mentor
Team Cub Mentor
 
Posts: 2560
Joined: Thu Aug 03, 2006 6:20 am
Location: OH West Mansfield
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety Award
Circle of Safety: Y

Re: 750 JD compact tractor

Postby JackF » Sat Jan 18, 2014 10:40 am

Gary Dotson Stated: but I'll bet Jack found your answer

Thanks Gary, I appreciate the compliment, especially from you, but Steve is the one who pointed the other site out and thanks to KenL from mytractorforum for finding the problem.

At the end of KenL's post on the other tractor site, it was asked what caused the pump to split? I was wondering if the Yanma oil pump is a Trochoid Oil Pump style like the Clymer engine you were talking about.

Just an guess…If that’s the case and the tractors is in a cold climate and a heavy weight oil is in the crankcase and oil pump gears, when the engine is started and the oil pressure relief valve doesn’t open very quickly, in my opinion the pump will split open.

If you’re using 15w-40 Engine oil and the pump split open like KenL’s tractor did, I think I would talk to the Yanma people for an answer.
I’m really good at doing nothing…With that said…I’m really, really good at doing nothing
JackF
10+ Years
10+ Years
 
Posts: 905
Joined: Sat Feb 15, 2003 7:20 am
Zip Code: 00000

Re: 750 JD compact tractor

Postby birddog » Sat Jan 18, 2014 2:16 pm

Thanks for the link Steve. The trouble that the poster had there sounds like a good possibility. I run 10w-30, but we had some 30 below nights and even though I waited tell it got back into the teens to start the tractor it may still have been to thick in the pump. I ordered a service manual for it, so now I'm waiting on that. It looks like the hyd. pump, injector pump, timing gears as well as the oil pump are all part of,or under the front cover.

I'll post what I find, if and when I find something.
Mark "birddog" Birdeau
User avatar
birddog
5+ Years
5+ Years
 
Posts: 343
Joined: Fri May 05, 2006 12:00 am
Location: WI, Catawba
Zip Code: 54515
Circle of Safety Award
Circle of Safety: Y

Re: 750 JD compact tractor

Postby birddog » Sat Jan 18, 2014 2:43 pm

With the 750 broke down we've been moving the last couple snows by hand, but with the plowed banks it's to much work. So yesterday I decided to see if the JD 40C would start so I could move the banks back. I got it started but to add insult to injury guess what? No oil pressure! I said to heck with it, either it'll get oil pressure or seize up, after about 10 min. it was up to normal. I expect the oil was just too thick to make it's way into the little orifice of the gauge.

There's even more insult and a lack of planning ahead. I've got 4 or 5 JD garden tractors that could handle a snow blower and 2 snow blowers that would fit them. Also I've got a JD M and MT and a loader with snow blade that will fit either one, also a JD A and a loader with snow bucket for it. But of course nothing ready to go, and with the snow blowers and loaders buried I need the 750 to dig it all out.

Sometimes I'm amazed at how dumb I can be. Next summer one of the snow blowers WILL be mounted!
Mark "birddog" Birdeau
User avatar
birddog
5+ Years
5+ Years
 
Posts: 343
Joined: Fri May 05, 2006 12:00 am
Location: WI, Catawba
Zip Code: 54515
Circle of Safety Award
Circle of Safety: Y

Re: 750 JD compact tractor

Postby Gary Dotson » Sun Jan 19, 2014 7:59 am

Mark, be sure to let us know what you find out, you never know, this might come up again for someone else. Jack, according to the manual, this engine has a gerotor style pump. I suspect it has an aluminum housing. I also suspect the cold temperature played into the failure, if indeed it has failed. Several years ago, we experimented with cold flow on different oils, a dixie cup with a few ounces of oil in the freezer overnite. You'd be amazed how thick 10w30 gets! I've seen engine failures caused by cold start lack of oil circulation, pan full of oil but the pump couldn't pump it. It makes one think twice before starting in very cold weather.
Gary Dotson
Team Cub Mentor
Team Cub Mentor
 
Posts: 2560
Joined: Thu Aug 03, 2006 6:20 am
Location: OH West Mansfield
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety Award
Circle of Safety: Y

Re: 750 JD compact tractor

Postby JackF » Sun Jan 19, 2014 8:43 am

Gary Dotson stated: this engine has a gerotor style pump

You’re correct Gary; I should have looked up the style of oil pumps, instead of going by memory.

I guess if the oil pressure came back, it must be the oil is too thick….Maybe the oil pump pressure relief valve is sticking open.
I’m really good at doing nothing…With that said…I’m really, really good at doing nothing
JackF
10+ Years
10+ Years
 
Posts: 905
Joined: Sat Feb 15, 2003 7:20 am
Zip Code: 00000

Re: 750 JD compact tractor (update 2-4 -14)

Postby birddog » Tue Feb 04, 2014 12:24 pm

Finally got the service manual and got up the ambition to pull the front cover. Yup, the pump was split in half. Sure was hoping that wasn't the problem, but then on the other hand, there is no doubt what the problem is. Now just have to find some money and hope the parts are still available. Other then the split, the pump appeared to be in good condition.

I'm going to add a pad heater to the oil pan, and in the future make sure it and the block heater are plugged in for at least an hour before starting. Hopefully this won't happen again.

IM000266.JPG
IM000266.JPG (80.79 KiB) Viewed 142 times
Mark "birddog" Birdeau
User avatar
birddog
5+ Years
5+ Years
 
Posts: 343
Joined: Fri May 05, 2006 12:00 am
Location: WI, Catawba
Zip Code: 54515
Circle of Safety Award
Circle of Safety: Y

Next

Return to Other Tractors and Machinery

Who is online

Users browsing this forum: No registered users and 2 guests