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Discussion Starter #1
Good afternoon, I am a new member to this site but have been reading and following along for some time. Thanks for having such a great site. I Was wondering if you guys could help me out I am in a bit of a pickle. A friend of mine brought me an Ariens ST 727 with a tecumseh H70 Motor. The main issue is that once the throttle was increased it would over rev to the point where it sounded like it was about to snap a rod. I started off suspecting the carburetor as the machine had sat for sometime. After cleaning the Jets and reassembling the carburetor the problem stayed the same. Before I started messing with the governor linkage I wanted to make sure it was not fuel related so I replaced the carburetor with no improvement. So I then went and made sure the governor linkage was moving freely and attempted to adjust the linkage. I was able to get it to the point where upon increasing acceleration it sounded somewhat normal however as soon as I attempt to blow snow it bogs down and regains rpms when I back away from the snow which tells me perhaps I did not adjust the linkage correctly because it doesn't sound like the governor is not kicking in when it is supposed to. Am I missing something? Any suggestions? I attached a couple pictures in case something stands out to anybody. Sorry about the long-winded Post just wanted to try to be detailed. Thanks for the help and thanks again for a great site!!
 

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If you need to buy a tachometer, I recently researched what to buy over on this thread..

http://www.snowblowerforum.com/forum/snowblower-repairs-maintenance-forum/78713-what-rpm-tachometer-should-i-buy-2.html

Bottom line....

I bought one of these low cost units and ordered it from Asia. It took forever to arrive so you might want to pay the extra $2 and order it from the guy in California since you seem to have a more urgent need.

I have not used it yet... but people seem to say it's good enough.

$7.14 (approx depends on exchange rates) shipped from Hong Kong...

Digital Engine Tach Tachometer Hour Meter Inductive for Motorcycle Motor FC0 | eBay

$9.35 shipped from California...

Digital Tach Hour Meter Tachometer Gauge Spark Plugs Gas Engine Motocycle ATV | eBay
 

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Discussion Starter #4
Thanks for the replies, I actually have a tach gauge on order. I'm just concerned I messed up somewhere because it seems to idle within a reasonable range but when I come into contact with snow it doesn't increase the engine to compensate like It usually does instead it just boggs down and returns back to speed once I back out of the snow.
 

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Thanks for the replies, I actually have a tach gauge on order. I'm just concerned I messed up somewhere because it seems to idle within a reasonable range but when I come into contact with snow it doesn't increase the engine to compensate like It usually does instead it just boggs down and returns back to speed once I back out of the snow.
I believe that symptom can also be due to fuel mixture running too lean.
Not sure but worth checking.
 

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It looks to me like the governor link at the block entry point (where it screws to the shaft clamp) is at to much of an angle? They are usually a little more straight in line - but not perfectly straight. It should be canted slightly - but your looks to be to much....

Either way I think your problem lie in the governor. Watch Donny boys vid's and see what you come up with.
 

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Discussion Starter #8
thanks for the responses. stuart80112, I set the carb to suggested factory settings but couldn't dial it in any further with the super high idle issue. Was kind of figuring/hoping a fuel mixture issue wouldn't cause such an extremely high idle (like high enough where I was afraid it was going to blow up). nt40lanman, that was my big fear , an internal governor issue. If I can manually move the governor linkage and it affects the rpms would that rule out internal damage? If not is there another way to determine without tearing the engine down?
 

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Discussion Starter #9
thanks bad69cat , The angle your referring to seemed to steep to me as well but thats the angle i have to set it at in order for it to not idle through the roof. Can't for the life of me figure what else it might be. there's no "intake manifold" on this model or maybe i'd suspect an air intake leak . I replaced the carb gasket between the carb and the motor just to be sure.
 

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That gov lever looks at the wrong angle to me.

The manual that can be found free online gives a procedure.


Loosen green screw. Turn and hold shaft counter clockwise with pliers. Swing the red lever in direction of blue arrow and hold there. Tighten green screw.
 

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thanks for the responses. stuart80112, I set the carb to suggested factory settings but couldn't dial it in any further with the super high idle issue. Was kind of figuring/hoping a fuel mixture issue wouldn't cause such an extremely high idle (like high enough where I was afraid it was going to blow up). nt40lanman, that was my big fear , an internal governor issue. If I can manually move the governor linkage and it affects the rpms would that rule out internal damage? If not is there another way to determine without tearing the engine down?
If you manually push the governor linkage, you are basically doing what the internal governor should be trying to do itself.

When you move that linkage by hand, you will open or close the throttle and that will change the RPMs. That's precisely what the internal governor tries to do.

It uses centrifugal force (aka centripetal acceleration) using small counterweights to respond to the RPMs of the engine.. this in turn causes the governor linkage to move the way you are doing by hand.. which then adjusts the RPMs.

So if the internal governor is messed up... it won't be able to push or pull on the linkages and therefore it won't be able to adjust the RPMs the way it's supposed to. The two extreme cases are an engine that runs way too fast with no load on it (because the governor isn't slowing it down)... or way too slow under load (because the governor isn't speeding it up).

Those are also your symptoms... sorry to say.

Make sense?
 

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if your linkage is as freely moving as the one in this video (advance to ~2:28):


and you've got no lost-motion due to looseness in the governor linkage and if the linkage is properly adjusted then I'd agree with the others suggesting that there may be an internal problem with the governor drive, counterweights etc.
 

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Blackfin makes a very good point!

There's two parts to this...

1) Does the internal governor push and pull when it should? This is hard for you to see from the outside because the motions are small. They become visible and exaggerated only by watching the linkages move in response.

2) Assuming the governor *is* pushing and pulling properly.. are the linkages too loose or too tight or out of alignment so that the governor motion is not being translated over to the throttle properly? If everything is working.. a tiny motion from the governor gets turned into a much bigger motion on the throttle plate.

You can check #2 from the outside using the videos people have posted.

If everything on the outside seems right... then you are back to thinking that it's the internal governor that is not pushing and pulling as it should and that would mean opening things up.
 

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Amen there guys. It's a pretty delicate balance when it's working right. It doesn't take much on either side of the equation to muck it up.
 

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i could be totally wrong, but it just looks odd that the linkage from the butterfly goes back to the throttle lever and not to the governor arm ?
 

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Discussion Starter #16
definitely will try that , I've only been loosening the nut and pivoting the arm and retightening the nut. Haven't addressed the shaft that you refer to in the pic . Thanks again i'll report back
 

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i could be totally wrong, but it just looks odd that the linkage from the butterfly goes back to the throttle lever and not to the governor arm ?
This video shows that the linkage DOES go to the throttle on a Tecumseh HSK70. I assume that's the same engine.. right?

 

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One other thought.. because the governor is supposed to pull the linkage attached to the throttle.. and this in turn pulls the butterfly on the carburetor... are BOTH of those things well lubed and free-moving? If they are too "stiff" then the governor would have a tough time yanking them back and forth. How easy is it to move them by hand?

$0.02
 

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Wait a minute... what's that THIRD linkage on the throttle plate?
I think there should be one going to the carb, one going to the governor.... but I see a THIRD thing on your pictures.

http://www.snowblowerforum.com/forum/attachments/snowblower-repairs-maintenance-forum/79641d1455384489-another-new-member-mass-please-help-img_1597-jpg

The one I don't get is in the second hole down just beneath the linkage that goes to the carb. Is it a spring-type thing?

EDIT: Something looks wrong.. I just googled this picture which shows how the linkages might be.
Are you missing a whole linkage going to the throttle lever?
https://c2.staticflickr.com/8/7459/11910331514_0ee3222191_b.jpg

I may not be comparing apples to apples though. When I google for H70 and HSK70 and Tecumseh 7HP I am not sure what the differences are.
 

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Discussion Starter #20
Thanks 404 I will try that procedure looks like I've been adjusting it incorrectly by just loosening the screw and pivoting the arm then retightening, rather than turning the shaft counterclockwise at the same time.
 
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