Help Please w/ a JD 4020D fuel system issue!!

MattF-8

Member
I am trying to help out a buddy who shut his ’68 4020 down after the transfer pump (fuel bowl style) was so clogged that it would barely run. He cleaned the screen and put the bowl back on and now it will not start. Here is where I get into the mix, I bleed the system starting at the filters, then at the inlet to the injection pump. So I then cracked the lines at the injectors but don’t get any fuel. I believe it has a JDB pump and when I crack the bolt on the right hand side it will start and run, but when I tighten it, the tractor shuts down. What am I screwing up???? Where are the bleed screws on the pump? Your help is much appreciated! Matt
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Larry is correct..
Remove the fitting on the top cover.. NOT JUST THE LINE, BUT THE ENTIRE FITTING..
NOW, start the tractor..
By the "looks" of the pump, it hasn"t been serviced in a while.. I wouldn"t be surprised if the flex ring was broken.
You could remove the side cover and hold a paper towel under the window and catch any debris that comes out and check for "coffee ground" looking pieces.. BUT, the fitting is gonna be the culprit.. Its NOT THE CAUSE, just the culprit..
 
You are correct, I don't believe much has been serviced on this tractor in some time! Now when you say the side plate, do you mean the timing cover plate located just above the "Roosa-master" serial plate? If I find the "coffee grinds" then the pump will need to be pulled and serviced correct? Thanks Matt
 
That bolt is a head-retainer bolt. Not meant to ever be pulled out unless you are taking the pump apart. When you take it out - it relieves internal housing pressure. Normally internal pressure is 2-4 PSI and it works against incoming fuel pressure that can be up to 60 PSI. If that internal pressure gets too high - it stops fuel from coming in. Sounds like you've got a failed plastic weight retainer in the governor and it's plugged up the return fuel circuit. Note that pump is "self bleeding" and will clear itself of all air if working correctly.
 
Ok, where is that retainer located in the pump? I am looking in my parts book and is it in the lower body of the pump? Part number AR51710 or AR69419? And if so, am I right in saying the pump needs to be pulled and rebuild? Thanks again, Matt
PS, poor old girl does need a bath!!!
 
The plastic (pellathane) retainer comes in the seal kit for $15. Can't say I ever bought just the retainer. Most that I do now (DBs and DB2s) - I eliminate the retainer and use a solid conversion piece that Stanadyne sells. But yes - if the plastic is broken it means the pump needs to be torn down and repaired. Not what I call "rebuilt" but that word means different things to different people. There is no cost-effective renewal process in an injection pump to bring worn metal parts up to new specs. It's basically "remove and replace" worn parts as needed.
The numbers you are citing might be for a complete governor weight assembly but I don't have any Deere parts catalogs showing those numbers. If the plastic has broken recently - you only need the new plastic. If the steel rivets have worn then you need the entire assembly or the new part that eliminates it all.
 
# 11 is the plastic dampener in the image Texas Jim posted. It attaches to #12 that has steel rivets on it that can get hammered off if run too long with broken plastic.

This is the timing window (from your photo).
 
Thank you Gentlemen for all of your help! Going back at it today. Had to have all new battery cables made up because they were so bad he fried them the other day from repeated cranking. To my surprise, two of the three where original! I would sure like to bring this old girl back to my barn and clean her! Thanks again, Matt
 

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