Governor spring

[Ian]

Has anyone got a reliable method of determining the spring length and/or strength to optimise the Listeroid governor for a specific speed ? Failing that, how did you go about optimising yours ?

I am aware that there are a number of posts about correcting governor linkage geometry, correcting lazy / fouling governors, and others but I cannot see any where spring selection has been the topic.

Was the spring supplied with your Listeroid even in the right ball-park to give you the right level of governing without further modifcation ?

The spring supplied (and a further 5 springs I ordered as spares) for my JKSon 12/1 was much too heavy and offered very poor regulation. I have tried a good range of softer springs and have improved the situation but think it can be improved further still and am now seeking guidance from people who may have a better angle on it than me.

Regards,
Ian

[gpkull]

keep on persistance will pay off. you may very well be the G spring man. havent had to mess with mine but when you get it right im shure everybody will want a part #.

[rpg52]

I installed the govenor modification kit from Utterpower, and haven't had to alter the spring at all.  Others have mentioned installing a much softer/longer spring to get good control.
Ray

[Jim Mc]

...and am now seeking guidance from people who may have a better angle on it than me....

Pretty simple, really.  Keep trying longer, weaker springs until the system becomes unstable (ie the speed 'hunts'), then go back to a spring a tad shorter or stronger.  It ain't rocket surgery...

[ronmar]

Well you need a way to measure output frequency, and a known load, preferably the maximum your configuration can handle.  This type governor will have some droop in the RPM as it takes an RPM change to command an increase in throttle to counter it.  If you have too low a spring rate, you will have excessive droop and at some point, the governor will hunt as the spring/flyweight combination bounces.

In going between 0-3KW of load, my PRM goes between 62 HZ and just under 58.  I can add a slight pressure to the rack and get back the RPM so I am not yet at full throttle.  That tells me my stock spring rate is just a little low.  One thing I have heard suggested is to use a second spring along with the first.  The differences will cut down on harmonics and provide a more consistent spring rate.  I have messed with it a bit and it looks promising, but I havn't found the right spring combination yet.  Mine is acceptable now and I had to temproarilly move on to other projects and will get back to that one this fall   

I can't think of any way to configure the governor spring weight other than trial and error though.  The first step is to perform the Utterpower modification and get the adjuster off the moving linkage.  This alone makes a world of difference.  Another thing is to try and remove any slop in the linkage.  The linkage needs to be loose enough to move but tight enough to transfer throttle commands to the rack from the governor.  One of the worst parts on mine was the little yoke assembly that connects the end of the rack to the top of the upper bellcrank. It was so loose, the rack would vibrate back and forthe and the RPM would hunt slightly because of this movement.  I tried several things, but what seemed to work best was a very light weight spring about 2" long unloaded.  I place this spring across the two attach points of the upper bellcrank.  One down where the vertical push/pull rod attaches to the lower point and the other end of the spring to the end of the rack itself.  This is a very light spring and it is just barely being stretched.  You could do the same thing with a light weight rubber band.  This pressure gently holds the yoke and fuel rack at one end of it's slop eliminating the un-commanded throttle inputs and makes the speed control a bit sharper.

Ron   

[Ian]

Many thanks guys.

I particularly like the idea of a light spring to take up slop in linkages and will give this a try.

Agreed, it is not rocket science. I have managed to improve on what I had but I am now struggling to improve further. I either get a spring that allows the engine to speed up when unloaded, or allows the engine to dip a little too much when under load. Alternatively, I have a number of springs that allows the engine to hunt when loaded or unloaded.

I will give the double spring a go as I had not thought of that. Many thanks for the tip. Just for clarification... are we talking about 2 springs in series with each other, or two in parallel ? Does it make a difference ?

Maybe I am at the limit of my particular linkage mechanism anyway and I may find that it cannot be improved upon. But I want to prove this to myself before I give up and just wanted to make sure that I was not missing something.

A neighbour has a Listeroid and he just got lucky with a part of a spring he had lying around that happens to be perfect - almost zero variation in engine speed between no load and full load.

Once again, many thanks for all the helpful tips.

Regards,
Ian

[rzrbax]

I have installed George's governor fix on a 12/2 and a 6/1.  Both were significantly improved.  It is a simple device, but then that's what this sport is all about (grin).  Somehow a computer controlled Listeroid is an oxymoron to the max.....................Bill Dempsey

[BruceM]

I added a second, very soft spring to a spring that was almost right but allowed too much hunting. The second spring is in parallel, and is even slack at the resting position.  This is the best I've found so far. 

I had to rebend the upper pivot arm for better alignment and drill and bush the hole for the sliding yoke that connects to the rack.  On my machine this was a very sloppy fit that sometimes bound up.

I tried George's kit on my unit before changing springs- it didn't do much on my machine- I think the spring was just too far off.  I'm still using it now as it's a better arrangement  by far.

My speed regulation is OK, though I wish it was better: 58 Hz full load, 63 no load (62 if the engine is cool).  Someday I'll add an RC servo with a piano wire spring arm to "nudge" the governor.

Best Wishes,
Bruce M