# Ariens 520 dies when not choked



## Vandykej17 (Jan 14, 2019)

Hi all,

New member here, trying to fix my snowblower that dies when removing the choke. I have an Ariens 520 with a Tecumseh snow King engine. It has 4 choke settings, from fully on to fully off. The snowblower will run fully choked and the next setting, but it almost instantly dies when moved to fully open and the adjacent setting. At first I assumed it was a carb issue, so I removed the carb, cleaned it, and put it back on. Still the same issues. 

So I tried diagnosing more. Since I am assuming my idle mix is too lean, I wanted to confirm that suspicion. When I started the snowblower again, I flipped off choke and pushed the prime button to force a richer mix. This kept it running fairly smooth, obviously i can't do this while snowblowing though 


I am wondering what your guys' thoughts are on my next steps. It's got to be a plugged jet or passage in my carb, right? Before having it serviced, does it make sense for me to buy a new carb from Amazon for <$20?

Thanks in advance,
Jake


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## jsup (Nov 19, 2017)

Yes, time to replace the carb. Those Amazon carbs work just fine, I have had a zero failure rate.


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## RedOctobyr (Mar 2, 2014)

Sounds like either the carb is still dirty, or perhaps you have an air leak around the carb that's letting in "raw" air. 

But either way, an Amazon/eBay carb sounds like a good solution. And certainly worth a shot before taking it somewhere.


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## Vandykej17 (Jan 14, 2019)

Okay, thanks so much for the quick replies! I'll order the carb, get it installed and provide an update.

Thanks again,
Jake


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## tadawson (Jan 3, 2018)

There are a couple of small ports on the base of the main jet that are easy to miss, but trivial to clean if you know they are there, so I vote clean it corrrectly instrad of downgrading to a 3rd world part that may bring in other issues.


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## tlshawks (Feb 9, 2018)

tadawson said:


> There are a couple of small ports on the base of the main jet that are easy to miss, but trivial to clean if you know they are there, so I vote clean it correctly instead of downgrading to a 3rd world part that may bring in other issues.


Yep. Something didn't get cleaned. I've seen those nuts have one port, I've seen them with two. Either way, if those don't get completely unclogged, still ain't gonna run right. And yeah...I always re-use the original carb. Might be more expensive to rebuild than a new cheap carb, but I tend to never have issues with a properly cleaned and rebuilt carb.


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## Vandykej17 (Jan 14, 2019)

I got the new carb, and initially it looks a lot better. It can run with the choke completely of, once warmed up. I might still look at a rebuild kit and rebuild my old one.

I have a follow up question. When I have the throttle all the way up, and the engine is running, the carb throttle valve that is closest to the engine is all the way closed (resting against the idle screw). But if the engine is not running, that throttle valve is correctly wide open. I thought if the throttle is all the way up, the throttle valve would be wide open all the time. Is it working correctly? Will the throttle valve open up more of I'm actually throwing snow?

Thanks,
Jake


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## Kiss4aFrog (Nov 3, 2013)

:welcome: to SBF Jake

When the engine isn't running the governor is trying to pull the throttle full open.
When the engine is running the engine speed control lever will pull the throttle open to a point and if the engine encounters something to slow down the RPMs the governor will apply more throttle until the set level is reached and then lets the linkage go back to rest at the throttle levers setting. Even when you have the throttle set to it's highest speed the throttle plate won't be fully open as there should always be more the governor can open it to maintain the set RPM. 

I'm not sure what you mean when you say it's resting on a screw as all I can see in my mind is the idle adjustment screw.

.


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## tlshawks (Feb 9, 2018)

High speed set screw?

A 520 to me means it might have an HSSK type engine. I know when I was looking at different Tecumseh docs, certain HSSK's would have a setup where they had not only a low speed set screw but also a high speed set screw.

Of course, the HSSK40 I was working on (1971 I believe) didn't have the high speed screw...

Maybe we need to know what Snow King engine we're actually talking about here. I'm pretty sure my HSSK50 Snow King (early 80's) has a high speed screw setup on it.


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## Vandykej17 (Jan 14, 2019)

Kiss4aFrog said:


> I'm not sure what you mean when you say it's resting on a screw as all I can see in my mind is the idle adjustment screw.
> 
> .


Yes I meant the idle adjustment screw.

I didn't know the snowblower had a governor... I thought "A" in my attached image was just a means of attaching my throttle setting to the throttle plate "B" through the spring and the throttle linkage. After reading about it, am I understanding correctly that "A" is the governor and it attaches to the crankshaft which adjusts based on if RPMs dip too low (when it's throwing snow)?

If that is true, why is a a throttle lever necessary (the red lever)? Doesn't the governor determine the engine's throttle all the time?

Thanks!


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## Vandykej17 (Jan 14, 2019)

tlshawks said:


> Maybe we need to know what Snow King engine we're actually talking about here. I'm pretty sure my HSSK50 Snow King (early 80's) has a high speed screw setup on it.


I have the Ariens 939003 (ST520E). According to the parts diagram that has the following engine:
ENGINE, 5HP TEC LH195SA 120V | (939003).

I don't believe it has a high speed set screw, but I obviously could be wrong considering I also wasn't aware it had a governor. 🙂

Thanks!


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## tlshawks (Feb 9, 2018)

Did you adjust/change the governor at all, meaning - when you re-installed the carb, did you first get the governor link (what attaches from the top of the governor arm to the carb throttle) to the correct hole on both the throttle and governor arm?

You will see the action with the heater box off when you raise (increase) the throttle. It should turn B in your photo to where it is partially open - the inner throttle plate will go from closed to partially open as you lift on the throttle. As long as that governor link at the governor arm is in the same hole, and the governor link is also in the same hole on the carb as the prior carb, and that spring attached to the governor arm halfway down is in the same location, all those should work as they did prior. If my memory is good, the spring tension changes against the governor arm as you raise/lower the throttle lever, causing it to move and therefore change where the throttle plate is, increasing/decreasing engine speed.

Get any of those on the governor or throttle "one hole off"...



Hopefully, you took several pictures of all the linkages in this prior to disassembly so you know exactly where all the pieces of the puzzle fit together when re-assembling. You need to take what amounts to 3-4 pictures...left side, straight on, right side. Like I say, raise and lower the throttle and see how the throttle lever works with the governor arm/link/spring with the throttle shaft on the carb itself.


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## tadawson (Jan 3, 2018)

Vandykej17 said:


> Yes I meant the idle adjustment screw.
> 
> I didn't know the snowblower had a governor... I thought "A" in my attached image was just a means of attaching my throttle setting to the throttle plate "B" through the spring and the throttle linkage. After reading about it, am I understanding correctly that "A" is the governor and it attaches to the crankshaft which adjusts based on if RPMs dip too low (when it's throwing snow)?
> 
> ...


The red lever (throttle control) allows the user to set what speed they want the engine to run, between idle and maximum, by applying variable spring tension to the gov arm/link/throttle plate. With the engine running, the gov applies counter pressure to that spring to maintain constant engine speed. The engine slows, the spring holds the linkage against the gov spool ad it recedes, increasing throttle. The engine speeds up, and the gov spool advances and pushes the throttle closed against the spring.

Note that a given throttle plate opening does not directly determine engine speed, but rather the energy put into the engine, and resultant speed will be determined by that as well as load. Note that the throttle plate has to be open amlot further to run 3600 RPM when blowing heavy snow than it does when parked with the augurs not running.


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