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1980's john deere 750 tractor with yanmar 1.3l diesel

10K views 13 replies 8 participants last post by  ARoman 
#1 ·
My dad ended up buying a john deere 750 a couple years ago Ive used it alot to brushhog the fields behind the house and level out the driveways with the backblade it is a good tractor just lacking a little power (only 20 hp) it has the three cylinder 1.3L yanmar diesel engine and im looking for ideas and suggestions to add a little more power to it because even in a low gear it really boggs down cutting thicker grass and weeds with the 60 inch pull behind mower. Anyone tinker with these little japanese diesels before?
 
#2 ·
You might try MyTractorForum.Com


I don't know about your specific motor, but I've seen threads on there where people added turbo's to their small engines.


Or you could just find a higher horsepower engine with a similar crankshaft and swap that in.
 
#3 ·
They are very dependable motors. I have had several in boats and it always amazes me how you can put them away for the winter and they fire right back up in the spring with maybe one turn of the crank.

That said, short of a turbo I don't think you are going to find any extra power in there.
 
#4 ·
it is one tough reliable engine, while servicing the tractor last night found the left brake shoes hanging up, could be part of my problem. Gonna replace them and see how it does from there. I was thinking maybe a turbo from a vw tdi jetta :D theres a couple for sale around me that they dont want much for.
 
#6 ·
I had one of the John Deere 755 back in that era also. I had several issues just as you say yours is doing. I thought that I was going to just put in in the shop and rebuild it. Ahemmm, not so. Believe it or not I was told by several really good diesel mechanics that that motor is disposable. You can't rebuild them because of internal design. I then thought that I would just sleeve the cylinders. Again when you tear it apart you'll see that you can't. It's designed internally as a bunch of webbing. when you punch the cylinders for the sleeves the cutters on the bore will just break the casting and get hung up and really start tearing things up. Now, I say that as a fact back then and today someone may have a different style of boring equipment for that. Here's the real catch to your issue. That motor was only designed to last 600 to 700 hours. Not much, huh? Thanks, John Deere. I was told as a mechanic in a boat shop at the time you had to buy a complete engine - $4000.00, again that's back then. The good new is that they are absolutely complete. You do not need to swap anything out, not alternator or anything. It's all there. It only takes about 1/2 to 1 hour to swap it. It is a work horse little tractor. I replace the motor twice and I said enough! I sold it back to a FD dealership and bought me a Grand L 5030 Kubota. That tractor was awesome. The JD just got too expensive. I still have a bunch of brand new pieces around somewhere that you could have. It's been a long time since I've seen them though. Well, anyway that's what I found out and good luck.
 
#7 ·
interesting, ive seen rebuild kits, sleeves, pistons/rods, and every gasket on the engine for sale online but dont know if its for my engine or not... remanned engines still go for 3-4 grand so if it comes time for a rebuild or replace ill probably just get rid of the tractor, we only picked it up for around a couple thousand a few years ago with a couple of implements.

good news is it starts up every single time with no glow cycle with pretty much no blow by, have not done a compression test before on it but it seems healthy for an old well used tractor with i believe about 600-700 hours on it already
 
#10 · (Edited)
There is a ton of life. In the marine world it is rare to see one not outlive the boat. I wish I knew exactly how many hours mine has. Could be as much as 3000, but I know it is over 2000. I have had two hour meters fail and have ran it for many seasons until I got around to changing the hour meter. I am over due for a valve adjustment but otherwise I have been told "just use it". And it a boat they work hard, it is not uncommon for it to run for 6 to 8 hours straight at 2800 rpm, never slowing down or stopping.
 
#11 ·
very true, they were after all designed to handle basically almost next to redline for days on end to run the PTO in tractors or to run in boats all day long. ive always been told super high compression diesels like these seem to last longer for some reason too, never been told why though.
 
#13 ·
Hey rattlindiesel, I also own a 1984 750 jd 4x4 with the yanny in it and it has around 2600 hrs on it and runs strong best little compact i've owned. Sits most of the winter idle come spring turn the key fires right off with the same fuel and runs all summer without a hiccup ,,,main thing to keep oil changed and keep up with filters ,,,oil,fuel,hyd. this little machine seems like it may never dye, gets me in some tight areas where the kubota wont fit and the loader on it is very useful, also have the backhoe for it to, not the strongest for digging fast but it will get it done if you have the time fun little toy ....good luck with it and let us know how it works out for you
 
#14 ·
Best tractor I owned so underrated and so dependable. Broke mine in the moment super hard to find parts but my mechanic said to find the parts because he says those engines are beautiful and he has fixed endless amounts of John Deere. We own new Holland’s fords case kubotas but nothing compares to a John Deere maybe the hollands and kubots are a bit more strong and stubborn but these John Deere’s you can work 14 hrs and not be as physically beat
 
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