John Deere 820 3 cylinder injector issue

Zoom45 · Sep 20, 2024

Got a 1971 (I think) 820 3 cylinder. Its been running ok but the the fuel filters were extremely dirty so I replaced them. It ran good for a couple of weeks then started missing. I found the return check valve had some trash so I cleaned that out and it ran ok for a while. It started missing and smoking a little so I ordered new injectors from Ebay and put them in. It was fairly easy to do just used a heel bar to pry them up. I also put new seals on the injector line caps then cranked it up. It runs rough idling and smokes and seems to have raw fuel at the exhaust manifold and pipe joint. It will run wide open and the smoke clears out some but still idles rough. I guess a new injector is stuck open and leaking. How can I determine which one it is? I cracked the injector line caps with it running and fuel leaks out equally and all cylinders seem to act the same. Any ideas?
Thanks
Zoom45

beenthere · Sep 20, 2024

Welcome to TBN

Maybe thepumpguysc will see your plea for help and chime in. He's the best one I can think of as you may have been making more problems for yourself than fixing. I'm not sure. Good luck.

thepumpguysc · Sep 20, 2024

Put the old injectors back in and see if the problem gets better.. u have nothing to lose.
I tell people all the time not to buy that type of injectors online.. I’ve tested TO MANY of them to endorse them..
WHAT IVE FOUND IS, they’ll either have the wrong nozzle in them, be set at the wrong pressure or the pressure will be 1000 psi different than the others in the same set..
I’ve even pulled some apart because they wouldn’t atomize properly and found metal shavings in them..

So take it as u like.. but I would put the old set back in.. just to verify the online injectors are worse than the others..& if your findings are correct, get your money back.
Have a close look at the description online.. most of the sites have a list of about 50 injector numbers or engine numbers that theirs supersede.. it doesn’t work like that..
They also “recommend” changing them “in sets” due to variations in fuel delivery..
It doesn’t work like that either..

Zoom45 · Sep 20, 2024

Thanks. I'll swap them back tomorrow. I just need to run and get new seals for the return tee caps. Funny, after I let the tractor sit a little while, I cranked it and it runs pretty good now at idle and doesn't seem to be leaking in the exhaust or smoke anymore. Can a leaking or stuck open injector just start working right on its own? I have a drip on my second injector line so need to fix it too.
Zoom45

thepumpguysc · Sep 20, 2024

Yes, it’s possible that a stuck injector (open or closed) does fix itself..

Zoom45 · Sep 22, 2024

I swapped the injectors back but before cranking it back up, I decided to pull the fuel tank out and clean it up. It had a lot of dirt in it and was seeping fuel at the bottom. After cleaning it I could see some tiny pin holes in the bottom so I had to fix those. While the repair is curing I want to replace the fuel hose on the return tees. What is the correct size to use? I have some 1/4" but its too loose.
Thanks
Zoom45

thepumpguysc · Sep 22, 2024

I think it’s metric.. 6mm.??

Tx Jim · Sep 23, 2024

I located Diameter: 0.156" (5/32") or 4mm by Googling part # R68281

Zoom45 · Sep 23, 2024

I got 3/16 and it fit good. Got the old injectors back in it and returned the ones I got on ebay. It cranks up and idles good and it will run up to about 2000 rpm but while clipping the pasture it will bog real bad in taller grass until it almost quits. It seems to just lose power under a load. I have flushed all the lines and tank, it has new fuel, new filters, new check valve on the pump return line. The new injectors seemed to be flooding the engine so I put the old ones back in. What can cause the bogging-a bad pump? What should I look at next?