JD 4720 doesn't go as fast as it should

   / JD 4720 doesn't go as fast as it should #21  
ok. well I didnt get the option with my machine but I suspect you do. im reading my manual and it says it is activated through your cruise control switch which explains why your speed only goes to 7 and your cruise light is on. Turn off the cruise control. the switch should have a picture on it like the indicator on your dash. I would check mine but it is at the dealer for warranty work. I can take a picture of what the manual says about how to activate speed match but give me a minute. Once you turn off your cruise, the indicator should go off on the dash and your machine should be good to go for 18mph
 
   / JD 4720 doesn't go as fast as it should #22  
Click the image to enlarge it. I spilled some of my burboun on it. tells you how to turn off at the end. guess I was wrong about turning the switch off on cruise. looks like there is another simple step to turn off but involves cruise switch
photo.JPG
 
   / JD 4720 doesn't go as fast as it should #23  
Click the image to enlarge it. I spilled some of my burboun on it. tells you how to turn off at the end. guess I was wrong about turning the switch off on cruise. looks like there is another simple step to turn off but involves cruise switch
View attachment 333181


I haven't used the speedmatch function on my 4520 but would have assumed that if you turned the key off it would need to be reset to use again. Interesting to see how this works out.
 
   / JD 4720 doesn't go as fast as it should #24  
Sure sounds like the speed match. My manual like above tells how to turn it off and states nothing about turning the key off resetting it. It will be interesting to see how OP responds after going through the procedure. I have a 2007 4720 as well but do not have the speed match option. to try it on.
 
   / JD 4720 doesn't go as fast as it should
  • Thread Starter
#25  
I tried to get it working this morning. Don't think I have speed match. I was able to lower the mph by .5 at a time by toggling the cruise switch but couldn't get it to go up. Also, the instructions refer to an acceleration and deceleration switch, not sure what that is.

I called JD to see if one of the techs knew, they are to call me back.
 
   / JD 4720 doesn't go as fast as it should #26  
Is the motor dying down while trying to accelerate to 18mph? If it is not dying down, you are either in range B or have speed match on. Range b has a top speed of 7mph. If your rpms are up at 2500, and you have the pedal to the floor maxed out in c range, its the speed match. Even with dirty filters, you would hear the motor fighting while turning the pump to achieve top speed
 
   / JD 4720 doesn't go as fast as it should
  • Thread Starter
#27  
Danscaper, thanks for that. The tractor accelerates just like a 4120 we have but stops at 8mph. It is definitely in C.
I took it to John deere last night and they will hang the computer on it.

I think it is something simple like speed match but have no idea how to turn it off or reset it. I don't have a switch like the manual says.

I'll post when I hear back from them.
 
   / JD 4720 doesn't go as fast as it should #28  
Don't know about yours, but with mine you can't get top speed without running the engine at PTO rpm. Apparently the pumps can't move enough fluid at slower rpms to reach top speed. Try it.
 
   / JD 4720 doesn't go as fast as it should
  • Thread Starter
#29  
Thanks, yes, I had the throtte full, it maxed at a little over 2500 rpm, just above PTO. I got up to 8.0 mph this time, .4 more than last trip... still not good.
 
   / JD 4720 doesn't go as fast as it should
  • Thread Starter
#30  
The problem I'm still having is following the instructions for the speedmatch. My guess is I do NOT have it installed since there is not a seperate toggle for this in my cab.

The instructions refer to the "accel/decel switch", what is that?

Using SpeedMatch Option (eHydro)

SpeedMatch enables the operator to set the desired maximum travel speed for the machine. Full forward or reverse pedal travel distance can be used to control machine travel speed between stop and the desired maximum travel speed.

1. Depress forward travel pedal until desired maximum travel speed is reached.

2. Fully depress bottom of cruise switch to activate speedmatch function.

3. Fully depress bottom of accel/decel switch to set maximum travel speed.

4. Release forward travel pedal. Completely depress forward travel pedal to achieve desired maximum speed.

5. Adjust maximum travel speed:

· Fully depress top of accel/decel switch repeatedly to increase speed by increments.

· Fully depress bottom of accel/decel switch repeatedly to decrease speed by increments.

6. Fully depress top of cruise switch to return switch to middle position and disengage speedmatch.
 

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