(2001) JD 5420 RPM loss under load

   / (2001) JD 5420 RPM loss under load #1  

Frank444

New member
Joined
Jul 19, 2022
Messages
3
Tractor
John Deere 5420, 5410
Looking for help.
2 weeks ago I was doing some brush hogging and notice about a half hour into it that the rpm’s would drop from wide open 2500 to 21-2200 once the engine reached full operating temp. Thinking it was water in fuel I drained the petcock nothing out of the ordinary.
Yesterday I started mowing a hay field yet again 30 minutes or so passed by same symptoms drained fuel filter worked fine for a pass then fell back down to a constant 2100 rpm’s no hesitation or unusual sounds injectors etc.
This morning I places a new fuel filter on it ran great till it hit operating temp for about 30 minutes again.
After talking with John Deere I drained a full tank of fuel in search of a filter inside of tank no filter was present. There is no inline metal pre filter before the secondary with the water drain petcock.
As you can guess Im having issues priming it currently read manual know procedure going to add compressed air with a rag around it in fuel tank to speed up process tomorrow..Other than the small check valve being plugged what could be the issue with the rpm loss and lack of power. I apologize for the long explanation but I can’t seam to find help anywhere.
 
   / (2001) JD 5420 RPM loss under load #2  
Welcome to TBN

From your description, sounds like the throttle is losing friction grip and just needs some adjustment so it doesn't drop rpm
 
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   / (2001) JD 5420 RPM loss under load #3  
Do not have an answer, but you might consider the following; 1) Replace the fuel and return line; 2) take off the tank and wash it out. I have done both of these items and it took me an afternoon to get the tank off/wash and an afternoon to replace the lines and put everything back together. My 5210 is open station the hardest part was getting the 2 little Philips screws out on the tank straps.

On priming, fill the tank, then disconnect the fuel line at the fuel filter and wait for the fuel to come out and reconnect it. This what I did (I had shut off the fuel at the fuel filter before starting the tank cleaning) and I did not need to prime, just turn the key and it started up.

If your not already doing this consider using JD winter/summer additive.
 
   / (2001) JD 5420 RPM loss under load
  • Thread Starter
#4  
Welcome to TBN

From your description, sounds like the throttle is losing friction grip and just needs some adjustment so it doesn't drop rpm
I almost thought the same thing but once it has cooled off and restarted it will rev back up for a while. And it worked great with the new filter .
🤷‍♂️ Pape JD has the check valve I’m going to buy all new rubber line and replace that, clean the top primer portion of the fuel filter housing disconnect Hard lines blow them out and give that a shot. I don’t know what else to do ?
 
   / (2001) JD 5420 RPM loss under load #5  
So it loses rpm but the throttle lever stays in the same set position ??
 
   / (2001) JD 5420 RPM loss under load
  • Thread Starter
#6  
So it loses rpm but the throttle lever stays in the same set position ??
Correct. JD says injection pump internal governor could be acting up.
 
   / (2001) JD 5420 RPM loss under load #7  
Then this TBN member might be a big help to you. Give him a shout through a pm as he knows his stuff.

thepumpguysc

 
   / (2001) JD 5420 RPM loss under load #8  
If the gov ring was breaking up it would shut the engine down..
When u get the drop in rpm’s, have someone there that can grab the throttle on the inj pump and pull it back to wide open and see if it’s a simple adjustment.(rpm’s pick up)
 
   / (2001) JD 5420 RPM loss under load #9  
Welcome to TBN
Have you checked to be sure fuel tank is venting? Try operating engine with a shop towel covering fuel neck. Do you have good fuel supply from tank to IP?
 
 
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