Lazy Governor - Help

[veggie]

I have a governor that hunts back and forth regardless of the speed adjustment on the threaded rod.
Conditions:
- First smoke
- No cooling system yet
- No load (of course)
- Regular diesel Fuel
- Gov. linkage has been checked and seems to be free of any drag

Anyone have any ideas on how to solve this ?

Thanks,
veggie

[billswan]

I agree with jens put some load on, if that doesn't help try lengthening the vertical linkage.

So is this a new engine or a rebuilt?

My 10/1 wanted to run away when the load on the gen would abruptly drop out, the vertical linkage turned out to be just a thread or 2 too long.

Now if you try this try to remember how much you change it so you can go back if it makes things worse.

Billswan

[veggie]

As suggested, I will add some load.
It may be a few days before I report back. I need to add a cooling system yet.

thanks,
veggie

[Ronmar]

Good video.  If you look at it closely, you can see/hear the RPM decrease conciderably before the spring suddenly pulls the throttle open to speed it back up. As suggested, some load could help, but it almost looks to me like the internal flyweights or the slider on the camshaft is binding or a little sticky.  As soon as the rpm drops enough, the imbalance between spring and flyweight gives the spring enough advantage to pull past the rough spot.  The throttle seems to close reasonably smoothly with rpm increase.  If this engine hasn't even been brought up to full op temp, things are probably not loosened up yet

as a suggestion, i would highly reccomend the utterpower mod to the governor spring.  Way easy and very effective.  Also pay close attention to the little forked piece that connects the linkage to the throttle rack.  This can also cause binding and inconsistemt governor response.  Mine was horribly fit...

[XYZER]

I had to get some run time before my governors settled down also I found the injection timing would influence the hunting issue.......

[veggie]

To compound the issue, these GM90 engines are available in two configurations, 750 rpm/6hp and 900 rpm/8hp.
The difference is the flywheels , governor springs, and injector pressure. (750 engines have spoked flywheels, 900 flywheels are solid webs)

I ordered a few of each speed and had my 750 rpm engines custom built with 900 rpm flywheels.
I'm thinking my 750 rpm engines got 900 rpm governor springs because the engine smooths out if I turn the speed adjuster up to 900. 
Fortunately I have both springs in stock.
More tinkering is necessary....

veggie