JD 6620 cylinder speed gauge

2underage · Feb 25, 2018

I have had a lot of my concerns about my 6620 answered on this site so once again I am asking for solutions for another one. On the last day that I was using the 6620 this fall I noticed that the gauge that reports the cylinder speed was not working. I checked the little belt that drives the gauge and it was ok and spun free. I am not sure where to look for the problem as it was working as it should until the last hour or so. I believe it must be either the gauge or the cable that drives it. What are your thoughts?

Bob · Feb 25, 2018

You might start by checking to see if the cable has broken, or is rounded off at one end or the other.

Ragnarok · Feb 25, 2018

The little bearings in the tach drive sometimes seize-up..looks like the belt is turning the plastic pully...but it's not.

Have seen the little pully strip-out and not turn the tach cable too(usually because of the little bearing).

Take the o"ring belt off and checkout the little pully see if it's turning the shaft...

4520BW · Feb 25, 2018

I guess the belt was crossed so it turned in the right direction. I drove 40 miles to a farm that said there 7720 cylinder speed would not work,seems someone noticed the belt was crossed when they greased it and put it on "right. The owner was hot that one of his guys changed it and some kid fixed it within a minute of being there.

JD 6620 cylinder speed gauge

2underage

Well-known Member

Bob

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Ragnarok

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4520BW

Well-known Member

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