# MTD Snowthrower Choke Issue



## Ralph_T

My two year old 2 stage MTD will only run smooth if I keep the choke half way when it's cold. Once it has been running for a while to warm up I try to turn off the choke but it idles up and down. It needs a little more choke after warming up the colder it gets outside.

So it seems as if the engine never heats up and it won't allow me to turn off the choke. It's as if the engine is constantly cold. At least the choke is acting that way.

If I start it in the summer it runs with the choke almost off but not quite all the way off.

It has been like this since I bought it and never really thought anything about it. Just wondering if this is normal? I have read a few articles saying that the engine could be running lean and that I might have a vaccum leak or lean mixture. It runs fine and has good power otherwise. Thanks for any tips.


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## GustoGuy

definitely Running lean. I would clean the carburetor on it since the main jet is most likely gunk-ed up a bit and not allowing enough fuel flow. Most newer carburetors have fixed jets and you can not adjust them. Make sure that the carburetor gasket between the carburetor and the manifold is not leaking too since that can lean out the fuel air mixture.


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## detdrbuzzard

hello ralph, welcome to SBF. once you clean the carb get a can of seafoam. take the gas is the can you use to refill the snowblower and pour it in your car or truck. get some fresh gas in your gas can for the snowblower and mix in the right amount of seafoam by following the directions on the can. seafoam works as a carb cleaner and fuel stabilizer


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## td5771

the glory of emissions carb, they stink. you would be able to make an adjustment but you cant. it needs a carb rebuild and it will get better.


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## GustoGuy

It it has removable jets you can just remove the main Jet and run some thread or super-floss through it with carburetor cleaner sprayed on it to clean out the obstruction thats causing it to run lean. On my Predator 212cc I enlarged the Jet slightly with super floss and polishing compound and cleaned with carburetor cleaner since it surged a bit when the temperature was below 30 degrees. It runs great now with no choke on even as cold as 0 Fahrenheit


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## td5771

if the machine is only 2 years old it probably has an emissions carb. hope fully it does not and it will take all of 20 seconds to solve his prob.

the nut on the bottom of the carb.....is there a screw sticking out of the center of it?


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## Ralph_T

Took the carb apart as far as I could go. Its a Huayi. When I got the 10mm bolt undone on the bottom of the bowl I got access to the float which when removed I could see the check valve needle and then I got in there and used a flat blade to undo the jet assembly. Nothing looks out of the ordinary and all orifices are clear. Prime squirter works good. So Im really at a loss what could be the issue. The gaskets seal great and are like new.


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## Ralph_T

I forgot to add that the engine still needs part choke even at slow idle. So this tells me that the idle jet is clogged. Does anyone know the location of this jet? Because as I said before the mainjet works fine because if I increase the throttle manually it will run fine with choke completely off. Make sense?


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## Ralph_T

Found the idle jet. Hard to believe I didnt see that with the carb off. I shoved a small piece of wire in it from my wire brush and a small plastic piece fell out. I think this might be it. Will test tomorrow.


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## Ralph_T

td5771 said:


> if the machine is only 2 years old it probably has an emissions carb. hope fully it does not and it will take all of 20 seconds to solve his prob.
> 
> the nut on the bottom of the carb.....is there a screw sticking out of the center of it?


Its a 2009 MTD YardMachines 2 stage with a Techuseh? The carb does have a screw bolt for draining at the bottom of the bowl. The carb says Huayi 34.


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## Simplicity Solid 22

Wooo Whooo...hope that plastic piece solves it for you Ralph...best of luck!!

That would be a nice find and fix hopefully...


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## Ralph_T

GustoGuy said:


> It it has removable jets you can just remove the main Jet and run some thread or super-floss through it with carburetor cleaner sprayed on it to clean out the obstruction thats causing it to run lean.


FIXED!. The problem was foreign debris in the idle jet. After warming up I can now open the choke all the way and it idles smooth. 

Gonna make it a point to check the idle jet once or twice a year from now on.


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## GustoGuy

Good to hear you got it running well. That Idle jet has a really tiny orifice and even the smallest speck of dirt can clog it up. I have used that super floss trick before to clean my carburetor jets on my snowmobile. It works well to remove varnished gasoline deposits from the main jet and it does not seem to scratch like a piece of wire could. I have lots of Toys. 2 snowmobiles. Personal Watercraft, A boat with a 50hp engine on it and a Doodle (bug) beast with a Predator 212cc on it and now my snowblower with a Predator 212cc. Despite good care I could never get that Tecumseh to run well and it would seem to go out of tune really quickly too. It was the hardest engine to start that I ever owned. I do not miss it at all. Thanks for writing back. Are you in the UP? or lower Michigan? Both can get dumped on with lake effect snow so its nice to have a good running snowblower to get it out of your driveway.


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## Ralph_T

I'm in southwest Michigan . Yes we get a bit of lake effect. 

I ran the snowblower again today and noticed that it takes about 7-10 minutes running until I can turn the choke off but eventually it will run without it after getting hot.

Is there anything I can do to improve this or is this normal?


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## GustoGuy

Yes, Since your engine is a 2009 model it is an emission engine and they are designed to run lean to reduce emissions. When its really cold they are known to surge since the engine is running leaner due to the increased density of the cold winter air. People have put in the next larger size main jet or drilled out the mail jet slightly to increase the amount of fuel. Since yours does run well when fully warmed up I would just slightly enlarge (super floss trick) or leave it alone. Enlarge it too much and it will run pig rich. I would not try to remove too much. You could just run a piece of super floss through it while spraying it with carburetor cleaner and that would work real well. It would clean out any gummed up or varnished gasoline from the inside of the Jet's orifice and could improve the flow enough to allow it to run better. I warm my snow blower up for a minute or 2 right before blowing as well since it is better on the engine not to overload it before it's reached its operating temperature


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## Ralph_T

Yeah I will just take the carb off again and clean it really well with carb cleaner. I'm just gonna leave the jet for now.

Getting a brief exhaust backfire noise through the exhaust every once in a while. Gonna try a new plug.


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## Ralph_T

Well guess what? The problem is back, just like before. It hunts up and down until I set the choke to halfway. So I checked the low speed jet and there are no restrictions. Starting to wonder if this has to do with the type of fuel we have in Michigan? maybe the winter blend with added butane? Going to try using some non-ethanol fuel. A carb needs to be set richer for ethanol so maybe that is it. All I am using is 87 octane E15. This is standard pump gas, nothing out of the ordinary. It's not like I am running E85 but it sure does seem like it! Just...eeerrh confused.

Let me know if you guys have any further suggestions. 

Also, would the spark plug gap have anything to do with this? I have a Torch plug that's been in there for the past 3 years and looks good but just wondering. Is the RJ19LM a direct replacement? I have a few of those laying around.


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## Midwest Mower Pro

have you checked the carburetor mounting gaskets? Maybe your problem was the jet at first, but if you did not replace the mounting gaskets, they could now be the cause of the exact same issue.

It may be worth finding a dealer who uses and Ultrasonic Cleaner and having them run it through a cycle or two. Just to be sure that carb is as clean as can be.

Can you get the model and spec number off of the engine? I can check to see what spark plug it calls for with that information. If you cannot find the numbers, the model and serial of the snowblower may give me the info I need.


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## Ralph_T

Midwest Mower Pro said:


> have you checked the carburetor mounting gaskets? Maybe your problem was the jet at first, but if you did not replace the mounting gaskets, they could now be the cause of the exact same issue.


It wouldn't make sense that a gasket just failed without being removed and damaged and reinstalled. This never happened between the last time I put it on and when it was running well. Nah. This would be the least likely suspect item.



Midwest Mower Pro said:


> It may be worth finding a dealer who uses and Ultrasonic Cleaner and having them run it through a cycle or two. Just to be sure that carb is as clean as can be.


This is a carburetor not an EFI with pinpoint injectors. I can well and see if there are any restrictions in the carb. And trust me there are NONE. I have been thorough and clean in my inspection last time. As a former aircraft mechanic I can vouch for my own accuracy.



Midwest Mower Pro said:


> Can you get the model and spec number off of the engine? I can check to see what spark plug it calls for with that information. If you cannot find the numbers, the model and serial of the snowblower may give me the info I need.


I can get it. Thanks though.

Fed up with these EPA carbs. It's bull that they make these so you have to replace them every couple years. Miss the old days.


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## Midwest Mower Pro

Ralph_T said:


> It wouldn't make sense that a gasket just failed without being removed and damaged and reinstalled. This never happened between the last time I put it on and when it was running well. Nah. This would be the least likely suspect item.
> 
> 
> 
> This is a carburetor not an EFI with pinpoint injectors. I can well and see if there are any restrictions in the carb. And trust me there are NONE. I have been thorough and clean in my inspection last time. As a former aircraft mechanic I can vouch for my own accuracy.
> 
> 
> 
> I can get it. Thanks though.
> 
> Fed up with these EPA carbs. It's bull that they make these so you have to replace them every couple years. Miss the old days.



Tecumseh engines are infamous for having microscopic pin holes in behind the welch plug where no brush can reach. Soaking with carb clean generally can't even clean these holes. Hence the term infamous. Ultrasonic carb cleaners are proven to be able to get these clean. I've seen it with my own eyes. Plus i'd say its pretty obvious it's not EFI with pinpoint injectors. It has a carb for goodness sakes. It obviously isn't EFI.

As to the main issue. If you are running on half choke to fix the issue, you are clearly getting too much air or not enough gas. So it's most likely either gaskets leaking or a dirty carb. It could be a host of things from clogged fuel line to a dirty air filter (I'm aware most snowblowers do not have air filters, but you get my point), but most commonly it's gaskets or dirty carbs. Not trying to insult your work, but it's definitely getting too much air or not enough gas if you have to choke it to run.


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## Ralph_T

Midwest Mower Pro said:


> ]Not trying to insult your work, but it's definitely getting too much air or not enough gas if you have to choke it to run.


I agree, but it's been doing this since the day I bought it. So some tool put the wrong jet in the carb cause the EPA held a gun to their head. Who knows? All I know is that I might have to end up buying a new carb because of someones mistake. Totally irate.


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## Midwest Mower Pro

Well if you supply me with the model and spec, I do a lot of business with Tecumseh. I will give you the best price I can on a new carb if you'd like.


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## Ralph_T

Midwest Mower Pro said:


> Well if you supply me with the model and spec, I do a lot of business with Tecumseh. I will give you the best price I can on a new carb if you'd like.


I would rather **** on a spark plug and plunge this thing off the grand canyon before buying any parts for it. It's just junk to me now. Thanks for the offer though.

By the way, my briggs and Stratton pressure washer just started acting up in the same way a few weeks ago. It has an EPA carb too. That's why I am leaning towards gas as a problem. Possibly too much ethanol in the supply.


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## Midwest Mower Pro

If you change your mind, let me know. I would like to try to ease your pain if you want to fix it. Fastest way to contact me is [email protected].

Sorry for all of your trouble!


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## Shryp

If you have ruled out everything but an emissions carb causing it to run too lean you could get some torch tip cleaners or some floss and lapping compound and open the stock jets slightly to get more fuel in there. Just remember, you can always take a little more material off, but it is pretty difficult to add it back after you remove too much.


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## Ralph_T

I can get a new carb for under $50 just shopping around on the internet. How much would a new jet cost? $2? What I need is a list of jet sizes and flowrates / application.


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## Ralph_T

Hey folks. Still have this issue with my MTD snow thrower.

I took the plastic jet out and stuck a piece of wire in through the tiny brass orifice and nothing came out. Put it back in and it ran the same. Last year and this year I had to run the choke half closed in order for it to run smooth. 

The problem is that the rpm's hunt at either full throttle or idle unless the choke is halfway closed. 

 So this year what I did was stuck a slightly bigger piece of wire down in there with hopes to maybe open the jet up bit. Well now it is surging really fast...and the choke has no effect on it whatsoever. 

So my thinking about this is that if I enlarged the orifice a bit to allow more fuel but now the choke has no effect anymore then the problem is too much fuel. 

Let me know what you guys think.


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## Shryp

Plastic jet? Are you opening up the low speed or the high speed? The high speed is under the carb bowl screw and you will need a good flat head screwdriver to remove it.


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## Ralph_T

Ok I know how to get to that high speed. Done it before. Will take a look again.

It's just strange that the surging/hunting happens at both idle and high speed. Do these carbs have a mid jet of some sort? 

I saw a passage in the carb which looked like it when through but ended in some type of welch plug which I could not get to. Perhaps there is a blockage there? It is really the only thing I have not gotten to inside the carb.

I will take a picture of the plastic jet with brass insert I am talking about that I have been messing with over the past few years.

Incidentally my local MTD service center mechanic said that I will need a whole new carb if I let gas sit in it over the summer. How that has anything to do with the problem is beyond me. I think he is blowing smoke up my rear. He wants $180 parts including labor total.


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## Shryp

It is true that if it sets too long with old fuel in it you might need to replace it. Sometimes that is cheaper than dealing with it. You can order the carb yourself and it should be pretty cheap.


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## Ralph_T

I would agree. Carbs are like $50 online. Is it possible the carb came bad from the factory? The reason I ask is that I have been struggling with this issue since the day I took it out of the box only 4 years ago. I have probably filled the tank maybe 5 times.

And honestly there really should not be any difference in a new carb from one that I completely dismantled and inspected. I see no problems whatsoever and I can blow air through all the ports. I am skeptical a new carb will help at all.

I think I screwed up my idle jet and will be ordering another of those. I will dismantle the carb again and go from there.


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## Shryp

Have you checked for air leaks on the gaskets holding the carb to the engine?


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## Ralph_T

Shryp said:


> Have you checked for air leaks on the gaskets holding the carb to the engine?


As far as I know this can't be done unless you install new gaskets to be sure. Please let me know if I am missing something.


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## td5771

Old fuel.. even a month or two old can cause the surging as well. I know you have the new style carbs (honda style/predator) They can be a pain but there is something stuck.

I have done a few and gotten the not to surge in stock form with no modification of the jets but they soaked in acetone for a week.

I got one to work fine that was being stubborn by throwing it away and putting a new one on.

Good luck ou shouldnt have a prob. You did this much you can swap out a carb.


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## Shryp

Ralph_T said:


> As far as I know this can't be done unless you install new gaskets to be sure. Please let me know if I am missing something.


I have heard you can spray carb cleaner, penetrating oil, starting spray or something flammable around the intake while it is running and listen for a change in the engine. I have never done it myself. I have heard you have to be careful spraying flammable liquids on a hot engine though.


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## Ralph_T

Ok so I got some results.

My family just bought a generator the other day which happens to have the same style engine and carb. So what I did was swap the low speed jets.

The results are that the generator ran normally and the snow blower ran bad as it always has. I had to keep it choked as before to keep it running smooth. 

So it looks like either something else in the carb on the snow blower is bad or there is a gasket leak. My next project is to swap the carbs and see if there is any difference.


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## Mr Fixit

Lets say your casting between the carb and the engine had a pin hole leak? 
I'm leaning towards leaking vacuum between the carb. Spray W-40 in the connection between the engine to the carburetor. Then a shot in key places, hunting for engine rpm change. Any change in engine sound is a guarantee your vacuum is bad. This is a 30 second test and so easy it's worth the effort. 
Prove it's inside the carb with this test if it makes no change on the RPM.
If you swap the Generator carburetors, remember to find out the differing HP so you can judge what you ended up with as a control trial.
Once you solve this, I'll get you all the 3 year old Craftsman Honda lawn mower engines with all the surge fun you can handle! W-40 proves everytime it's the throttle bushings. Can't be repaired!


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## Kiss4aFrog

Besides spraying flammable liquid you can also use a butane torch unlit to see if you get an RPM increase.


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## Ralph_T

Update.

Had some time to rip apart the snow blower carb...again. I wiped down every gasket and mating surface, make sure the gasket orientation was perfect and put it all back together. So guess what? It runs like a top now! So it appears it was a gasket leak. You got to be kidding me. All this time....

You guys think I should invest in a gasket set or just wait and see?


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## Kiss4aFrog

Buy the kit and run it as is as long as it runs right. Warmer weather, tear it down and rebuild with the the kit.


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