# Governor question Ariens 939003 (ST520E)



## Vandykej17 (Jan 14, 2019)

Hi everyone,

I have a few questions revolving around the governor. I recently replaced the carb, and while the engine still runs and throws snow, I don't think it runs like it should. I took off the governor lever (in hindsight not sure why) while replacing the carb and I'm suspecting I did not get it put back on correctly. I watched a few videos and set the governor by turning the throttle lever all the way up and tightening the governor screw as if it was pushing the throttle plate wide open.

First off, when I tighten the screw that goes through the governor arm, it gets semi-tight and then if I tighten it any more it loosens again. This makes me think there should be a nut on the other side of the governor lever clamp. Can anyone confirm if that is true? If so, this could explain all my issues if the governor clamp and governor lever can move freely of each other.

When I run the snowblower on low, it idles great. If I start throwing any snow on low, it bogs down, but doesn't fully die. When it bogs down, the governor arm does not move at all to open the throttle plate. This is my first reason to be skeptical of the governor not working as it should.

When I run the snowblower on high, it revs high, I'm not sure how to know if it's too high though. If I start throwing snow, it lowers rpms and runs great, but the instant I stop throwing snow, it revs high again. While looking at the governor arm it does not move between idle and throwing snow. I can screw out the "high-rpm no-load" screw on the throttle lever to fix the high revving, because the throttle lever might be overpowering the governor. It worries me to do this though, because from the scenario above, on low throttle, the governor isn't opening the throttle plate when it should. At some point if I screw this out too far there won't be any difference between low and high throttle, right?

What're your guys' thoughts?
Jake


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## KennyW in CT (Feb 24, 2015)

Watch Taryl Dactal's video 





at the 9 minute mark he shows the adjustment.


I had a customer with the same thrower, governor was adjusted the wrong way and would die once it hit snow.


There are only two ways to adjust the governor, CW or CCW with the carb at full throttle.


Good Luck
Kenny


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## KennyW in CT (Feb 24, 2015)

And there IS a nut under the button head cap screw. If it tightens then loosens the screw is stripped.


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## Vandykej17 (Jan 14, 2019)

KennyW in CT said:


> Watch Taryl Dactal's video


Yep, I watched this video a couple days ago to set it.



KennyW in CT said:


> And there IS a nut under the button head cap screw. If it tightens then loosens the screw is stripped.


This is most likely my problem. Is the nut attached to the lever clamp or could it have fallen off when I removed the screw? I will look in my screw bin tomorrow for a replacement to see if that helps.

Jake


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## Vandykej17 (Jan 14, 2019)

KennyW in CT said:


> And there IS a nut under the button head cap screw. If it tightens then loosens the screw is stripped.


After inspection of my governor clamp, there was not a nut that the screw attached to. I grabbed a spare nut from my stock and added it on the backside of the clamp. I attached a picture to be clear.


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## Bluejoe (Nov 29, 2016)

Problem solved??


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## Vandykej17 (Jan 14, 2019)

Bluejoe said:


> Problem solved??


Not exactly, but I do have more information. We got some snow today in Iowa so I took the black cover off the carb and I watched what was happening while snow blowing. Here are my observations. First, the snowblower died a few times while hitting larger amounts of snow. I was watching the governor while I could hear the engine bog down and the throttle plate was mostly closed, the governor was not attempting to raise the RPMs. I could however manually push the governor and open the throttle plate, so clearly it could if it wanted to.

When the engine is cold the governor seems to move freely on either slow or high speed. By move freely I mean if I move the governor lever with my hand, it will return wherever the springs are pulling it. On slow mode that would mean the throttle plate is closed, and on fast mode that would mean the throttle plate mostly open. 

When the engine is hot and on slow mode, the governor is still able to move freely, meaning if I manually push the governor to open the throttle plate, it will return to mostly closed when I let go.

This is where it gets weird... When the engine is hot and on fast mode, the governor does NOT move freely. If I move the governor lever, it will just stick at whatever position I push it to. I noticed this because I had the snowblower on slow mode (snowblower off) and when I raised the throttle lever to fast mode, the throttle plate did not open. But if I pushed on the governor lever, the throttle plate would open. If I opened the throttle plate half-way it would stay half-way open. If I opened it all the way, it would stay all the way open, and if I closed the throttle plate, it would stay closed. It almost seemed like the tension of the spring between the throttle lever and the governor lever was pulling the governor at a weird angle and thus was not moving in conjunction with the throttle plate very well. 

If there is friction inhibiting the governor lever from moving freely, would that cause it to not adjust the RPMs? Or would the governor just push past the friction?
Is the governor not moving freely a cause or an effect? By that I mean is something wrong with the governor itself when the engine gets warm? Or is something else wrong and the effect is the governor not moving freely? My first thought is that my throttle linkage (metal linkage between throttle plate and governor lever) could be in the wrong holes, but I am fairly confident it is the same as when I removed the carb. No idea about the previous owner though.

Any help would be greatly appreciated!
Jake


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## tadawson (Jan 3, 2018)

Yup, it would cause a problem. Look at that small thin spring that pulls on the gov lever, and you get a feel for how much force is involved . . . it's very small, so methinks you have found your issue. See if the area where the gov shaft exits the engine is gunked up, and perhaps try a drop of oil on that point. Verify that the adjustment is not wrong, and barring that, it's teardown time, since likely your gov has failed internally.


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## SimplicitySolid22 (Nov 18, 2018)

You have probably have watched them but doesn't hurt to look again.


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## Vandykej17 (Jan 14, 2019)

Vandykej17 said:


> When the engine is hot and on fast mode, the governor does NOT move freely. If I move the governor lever, it will just stick at whatever position I push it to. I noticed this because I had the snowblower on slow mode (snowblower off) and when I raised the throttle lever to fast mode, the throttle plate did not open.....
> 
> Is the governor not moving freely a cause or an effect? By that I mean is something wrong with the governor itself when the engine gets warm? Or is something else wrong and the effect is the governor not moving freely?


Looking back at my previous post I am realizing I could answer my own question. Given that the engine was off and that the governor moved freely in slow mode, but could not move freely once in fast mode, then it must be caused by that spring tension. That is the only thing that changed between those two scenarios. What about that spring tension could cause the governor to not move freely? If we get more snow, I will run the snowblower without the spring (I suppose I could test the same thing keeping it on low throttle) and see whether the governor tries to change the RPMs when applying a load.



tadawson said:


> Yup, it would cause a problem. Look at that small thin spring that pulls on the gov lever, and you get a feel for how much force is involved . . . it's very small, so methinks you have found your issue. See if the area where the gov shaft exits the engine is gunked up, and perhaps try a drop of oil on that point. Verify that the adjustment is not wrong, and barring that, it's teardown time, since likely your gov has failed internally.


What is the point of that spring? I'm kinda confused why there is a manual throttle adjustment if the governor is supposed to govern the RPMs. I will add some oil to the governor shaft area to see. I really don't want to tear apart the engine


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## Vandykej17 (Jan 14, 2019)

Vandykej17 said:


> What is the point of that spring? I'm kinda confused why there is a manual throttle adjustment if the governor is supposed to govern the RPMs.


I think I misunderstood what a governor's primary purpose is. Does a governor only limit the RPMs? I was thinking it would raise and lower RPMs, basically being a throttle control.

I am confused how much tension the throttle spring should supply. There is a screw on the throttle lever that adjusts how tight that spring is that connects to the governor lever. Should it only supply enough tension to pull the throttle plate wide open? I'm assuming if there is too much tension then the governor won't be able to close the throttle plate.

Sorry for all the questions,
Jake


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## tadawson (Jan 3, 2018)

The spring really is the key to the gov! How much tension it applies to the gov arm determines the speed the gov will maintain. That's why the throttle control changes spring tension, and the gov controls the throttle plate itself.

The spring is trying to pull the throttle open, and the gov is trying to close it. Where those forces balance is the set speed. If the engine speed drops, the gov pushes open harder and adds power. If the engine overspeeds, the spring wins and pulls the throttle closed. (This is also why a gov won't perfectly maintain speed . . . how much the throttle increases or decreases is based on change in RPM, so when running under high load, there *will* be some RPM sag in order for the gov to do it's job.


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## groomerz (Feb 7, 2015)

tadawson said:


> The spring really is the key to the gov! How much tension it applies to the gov arm determines the speed the gov will maintain. That's why the throttle control changes spring tension, and the gov controls the throttle plate itself.
> 
> The spring is trying to pull the throttle open, and the gov is trying to close it. Where those forces balance is the set speed. If the engine speed drops, the gov pushes open harder and adds power. If the engine overspeeds, the spring wins and pulls the throttle closed. (This is also why a gov won't perfectly maintain speed . . . how much the throttle increases or decreases is based on change in RPM, so when running under high load, there *will* be some RPM sag in order for the gov to do it's job.



Govenor and spring is a balance of opposing forces the govenor and the govenor spring. Where this balance occurs determines governed rpm
Your explanation of govenor spring is backwards though. The govenor arm force is derived from centrifugal force of the spinning govenor gear with weights inside motor. More rpm causes more force on govenor arm (govenor wins) which closes throttle to prevent over rpm.

Now when motor is under load and rpm lowers govenor force is less than spring force and (spring wins )and throttle opens increasing rpm. 




Sent from my iPhone using Tapatalk


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## Vandykej17 (Jan 14, 2019)

Okay, this is making a lot more sense. The governor will actively try to close the throttle plate if it notices high RPMs, but it will never apply force to open the plate; that is the spring's job.

Now that I actually understand the balance of the spring vs the governor I might be able to get this thing running well. I first will adjust the governor like in Tary's YouTube video. Then I'll make sure the spring is applying the right amount of tension to pull the plate open if the governor is not applying force, but not too much so that the governor can still pull the plate closed.

Thanks again for your time and help!
Jake


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## Vandykej17 (Jan 14, 2019)

We got more snow in Iowa, so I adjusted the spring to where I thought it should go, with the same results, bummer.

I broke down and took it to a local shop to have them look at it. They called me after a few hours and said I didn't have any compression in the engine. They are saying that issue is not worth fixing. I'm not sure they're correct, any thoughts? I'm planning on taking it to another shop to get a second opinion.

Does that diagnosis match my symptoms? I think this blower has a compression relief mechanism, so I'm wondering if they might've seen low compression due to that. I would hope they would know that info.

Jake


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