D6 5R D4600 governor issues

PhilC

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Hello All
I started my D6 for the first time in 40 years a few months ago and it would not idle and kept floating from an idle to way over-revving. The engine over revved that much that it overheated. It was running for about half an hour. Since then I have pulled the governor covers off and inspected all parts and could not find any thing sticking, seized or out of place. I thought maybe there was not enough oil in the governor and pump so I topped it up to the level specified in the user manual. Today I ran the engine again and it did the same thing. The only way I could get it to idle was to push the throttle lever on the injector pump all the way forward but that also stopped the engine. I have the control rods to the hand lever disconnected so I could control it at the pump. I did notice that the last 1/2" of travel had some resistance like I was pushing against a spring.
Is there anything else that could be causing this issue? The rack and pinion in the injector pump moves freely and does not stick or catch on anything. I turned the engine over while the cover was off and the governor shaft is turning. Oil ports all appear to be clear.
I think my next step is to remove the governor and pull it apart and inspect every part.

Regards

Phil

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Tue, Dec 11, 2018 4:05 PM

ccjersey

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I would be looking for a seized flyweight, missing pivot pin for same or maybe just lots of sloppy pivots and linkage clevises. Failing that a failed thrust bearing might do the trick, any of these wear points would possibly allow the flyweights to extend to maximum without transmitting the resulting force to the rack. I think the flyweights are in front of the injection pump housing on the D3400/D4400/D4600 engines with the governor spring and control in the compartment to the rear. The connection between front and back being the rack. Could be wrong and do stand to be corrected on that. So have you actually seen the flyweights?

D2-5J's, D6-9U's, D318 and D333 power units, 12E-99E grader, 922B & 944A wheel loaders, D330C generator set, DW20 water tanker and a bunch of Jersey cows to take care of in my spare time😄

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Tue, Dec 11, 2018 10:54 PM

PhilC

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Reply to ccjersey:

I would be looking for a seized flyweight, missing pivot pin for same or maybe just lots of sloppy pivots and linkage clevises. Failing that a failed thrust bearing might do the trick, any of these wear points would possibly allow the flyweights to extend to maximum without transmitting the resulting force to the rack. I think the flyweights are in front of the injection pump housing on the D3400/D4400/D4600 engines with the governor spring and control in the compartment to the rear. The connection between front and back being the rack. Could be wrong and do stand to be corrected on that. So have you actually seen the flyweights?

Hello ccjersey
If by flyweights you mean what the manual calls governor weight then yes I have seen them. They reside in the box at the back of the injector pump. They seemed to be free and little or no play in them but I will check them again. I did not look too closely at the thrust bearing but I will reinspect.

Regards

Phil

[attachment=51757]Governor.jpg[/attachment]

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Wed, Dec 12, 2018 2:31 AM

Dick Tucker_archive

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Reply to PhilC:

Hello ccjersey
If by flyweights you mean what the manual calls governor weight then yes I have seen them. They reside in the box at the back of the injector pump. They seemed to be free and little or no play in them but I will check them again. I did not look too closely at the thrust bearing but I will reinspect.

Regards

Phil

[attachment=51757]Governor.jpg[/attachment]

Many years ago I had problems with the engine running away on a D7 17A it turned out to be the gear at the bottom of the fly weights had severe wear and the bearing at the below the gear was shot. All of the teeth on the gear were worn off. Replaced the gear and bearing and governor worked like new again. Might be what is wrong with your D6.

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Wed, Dec 12, 2018 4:00 AM

edb

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Hi Team,
something we encountered when up working on Mike Meyers D4 with D4400 engine, we had some stickiness to the governor operation a bit like you but to a much lesser degree.
As I was checking the Governor over and noticed a rub mark on the High Idle adjustment rod--see scans added.
It was caused by the pin at the end of the long Governor lever that connects to the rack somehow being bent and/or the pin being fitted as shown, this way being opposite to the way the books show-- contacting the said adjuster rod.

A reversal of the pin and double check with a slight tweak to the alignment of the lever and all was well.
Do not bend lever too far as you will upset the alignment of the link rod to the rack and could cause binding here too and you would be back to square one with another problem.
Hope this helps.
Cheers,
Eddie B.
Attachment

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Wed, Dec 12, 2018 7:11 AM

PhilC

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I removed the cover plate, started the engine and used the rack bar to control the revs. The rack seemed free enough. Straight away I could feel the governor trying to increase the revs even though the engine was set to idle and it was already increasing in revs.

[quote]If the engine begins gaining speed and the rack isn't moving, or isn't going all the way to zero fuel, you should be able to manually control it by using your finger to push the rack one way or another. [/quote]
Yes I was able to control the revs using the rack but it seemed to me the governor was constantly trying to do the opposite of what it should be doing.

I tested the rack before starting the engine and it seemed to move quite freely.
I uploaded a video of me controlling the engine using the rack bar but for some reason youtube reversed the movie so the governor is on the left and it looks like my right hand instead of my left. Goes for 6.5 minutes.

[video]https://youtu.be/1wqvWzpKY9c[/video]

I am thinking that the governor weights are either sticking or too tight and they are not throwing out far enough to reduce the revs for a given throttle setting. Sometimes they free up and move to the correct location hence the reason the engine idles down correctly some times. If I get time tomorrow afternoon I will pull it all apart and recheck everything.

Regards

Phil

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Wed, Dec 12, 2018 4:56 PM

PhilC

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The reason I think it is stiff or sticking is this engine was working hard prior to being dismantled for new rings so it would have to have been working fine. No one has done anything to the injector pump or governors while it was pulled apart.

[quote]I'd say your next step is to take the governor covers off and run it to see what is happening in there. If something isn't apparent, you might have to disassemble, inspect and clean.[/quote]

Can you run it without the back cover on? It has adjustments for high and low revs as well as the oil path for the top bearing.

Regards

Phil

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Thu, Dec 13, 2018 2:03 AM

oldbeek

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I have an oil can with synthetic oil in it. For this type of a problem where tightness may be the problem, I just squirt all moving parts with it. usually works on grandfather clocks to cats. lots easier than tearing into things. worth a try.

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Thu, Dec 13, 2018 4:38 AM

Chuck C

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Reply to oldbeek:

I have an oil can with synthetic oil in it. For this type of a problem where tightness may be the problem, I just squirt all moving parts with it. usually works on grandfather clocks to cats. lots easier than tearing into things. worth a try.

Check that the throttle linkages were put back together correctly. Some thing might have gotten reversed while it was apart.
Chuck C

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Thu, Dec 13, 2018 8:47 AM

PhilC

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Reply to Chuck C:

Check that the throttle linkages were put back together correctly. Some thing might have gotten reversed while it was apart.
Chuck C

Hello All
Firstly thank you for all the suggestions. Today I had time to pull the governor apart and I found three things wrong.
Firstly the locking nut was loose on the small yoke assembly from the governor to the rack. Not a major issue as nothing can unwind anyway.
[attachment=51766]Governor 02.jpg[/attachment]

Secondly the retaining nut for the drive gear on the back of the injector pump had come loose and fell off when I took the cover off. Still not the cause of the issue though.
[attachment=51765]Governor 03.jpg[/attachment]

And lastly the cause of all the problems. The weights themselves are free but the retainer assembly (circled) is frozen to the shaft. I managed to get it to move but not free enough. I will have to dismantle the whole governor and clean up the shaft. I can see now that the governor would not have been working at all and I can also see why it was trying to increase the revs all the time as it was stuck in the stopped position.
[attachment=51767]Governor 01.jpg[/attachment]

Once I get this fixed I will finally be able to finish repairs to the hydraulics and refit the blade and put it to work😊 I wish I had the time and money to paint it.

Regards

Phil

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Thu, Dec 13, 2018 2:29 PM

Rome K/G

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Better disassemble that whole governor and clean and inspect it!! looks like a sh@% hole! those rollers in the back should be shiny as chrome, check the needle bearings in there too. Thats what happens when they sit around for ten years and not run or have the oil changed. Thats why I never just go and try to start an old tractor that has sat around for years, you can end up doing more damage than good.

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Fri, Dec 14, 2018 5:52 AM

D6 5R D4600 governor issues

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