Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I have an old Ariens ST504 snowthrower that has served me well for many years. It has worked well even already this season Have always drained gas after the season is over, run till quit, greased, etc... so it's always been well-taken care of. It's a 5 horse...and I believe it's a Tecumseh. Looks like it was manufactured in 1978 or 1979. My problem currently is with the carb I have just thoroughly cleaned -- because the engine was trying to die when under load. So cleaning was in order. I've always had to run the machine with the choke switch on full. Anything less...even at 3/4's choke would cause the engine to start sputtering. I'm currently desperate because I live in Syracuse and after 2 days and 24+ inches of snow...and more on the way... I know no repair center will fix this quickly as they're likely up to their ears in similar requests... so I'm on my own. Obviously my careful(?) preventative maintenance did not keep me out of trouble. My question is -- After cleaning this older carb thoroughly and putting it back together the issue I now have.... and didn't before I disassembled and cleaned ....is that when I reopen the petcock under the fuel tank and gas flows back into the carb...in a matter of seconds (5-10) I then get a very small stream of gas shooting out, what I presume is a very tiny "venting hole". It's near the top and on one side of the carb. Hole is about the size of a small needle hole. Somehow after cleaning, this issue has developed. Obviously I can't even "try" to start my machine with this condition. I did a search on this forum and noticed in 2009 someone posted the exact question I have. It was at the tail end of comments about a similar Ariens carb problem. He too noted fuel squirting out a very small hole near the top of the carb assembly. Unfortunately no one responded to his question... so I'm lost. Any advice? Suggestions? thanks. Jack F

This may be unrelated, but here goes:

My wife's uncle was just here this weekend splitting some wood with me and we were talking snowblowers (he is very mechanical, I am not).  He had his snowblower (early 80's model, not sure the brand) apart at home, and said that when he put the carb back together, gas was coming out of a hole.  There was a float that floated up, but there was nothing on the float that would block that hole.  He looked around and found on the floor a small piece that connected to the float that would block the hole, and installed it and everything was fine.  Would be an insane coincidence if this was in any way related to your issue, but figured i would share

Good luck,

Dan

Additional Note ... I notice now that when I push the rubber primer bulb before starting the engine that the gas will squirt out the tiny hole. If the bulb is pushed 3-4 times as if priming prior to start, the fuel squirts out. I can start the engine and it seems to run fine now...with the exception of the dangerous gasoline stream (*though very small) right next to the exhaust. JF

If you have to run the engine with full choke, the carb is NOT clean.  Your main jet is probably plugged.  A carb has to be taken completely apart to be cleaned.  Every jet, orifice and gallery has to be known to be clean.   Get yourself some thin multi strand copper wire and take one strand off to clear holes, galleries and jets.  Spray WD-40 through them after the wire treatment then blow everything out with compressed air.  Once that is done, the engine should run without the choke.  The gas leaking from the carb sound like the float needle isn't seating properly.  Could be caused by a couple of things.  Your float might have fuel in it, if it's a hollow type or it may be mis-adjusted.  It could also be that the float needle is contaminated/worn or the float needle valve seat is contaminated/worn.   Carburetors are sensitive instruments and do not require much to put them out of commission.   

Thanks..Borat and Daniel...will take your advice and take a look at these... I did notice when I removed the needle from the base of the carb...the small rubber gasket seems to show some signs of deterioration. This rubber gasket seems to be about the diameter of an eraser on a pencil. it's mounted just above the spring that surrounds the needle. Wonder if this is a part that can be found...if necessary. Hmmm. Will disassemble that carb again and soak everything overnight. Keeping my fingers crossed. The float seems to be okay..doesn't have any fuel inside but would probably be a good part to replace after 30 years. If that float has a little piece attached that seals off that vent(?) hole I can see where this might be a good thing to inspect ;-) JF

The float acts on a lever.  One side has the float, the other side of the fulcrum (pin) is a piece of flat brass that the float needle rests on.  Sometimes there is a very small wire clip that holds the float needle onto the brass plate so that it follows the movement caused by the float responding to fuel level.   Maybe someone here has an exploded view diagram of your carb that they can post.  It will help you understand where everything is and how it all works.  The small gasket on the bottom of the carb is a seal to keep fuel from dripping from the adjustment needle on the bottom of the float bowl.  If it's not leaking, don't sweat it.  

Here are your diagrams:
http://outdoorpowerinfo.com/repairs/tecumseh_carb_632334a.asp

Make sure the bowl has the step lined up with the float pin.
If you want to test the needle and seat you can hold the float up and blow in the gas line.
To test the float you have to pull it off and shake it next to your ear and listen for anything inside it.
If you hold the carb upside down, the distance between the far side of the float and the seat where the bowl goes should be 11/64" and can be tested with a drill bit.

My thanks to all of you. As a novice who'll attempt almost anything (and always have parts left over) you've put me on a course to repair success...I hope. After the mention of the needle attached to the float...I suddenly thought.."Hey, something's missing here." That part had fallen off, probably when I removed the cup on the bottom of the carb. I found it on the floor after looking around for that tiny part So sure enough...that's likely why the gas was coming out of the small hole... nothing to seal it off. I've taken your advice and removed the carb...then detached the float and set aside...then put the whole assembly in a small can I filled enough with carb cleaner to cover all the necessary areas. Surprise of surprises...didn't take long for the cleaner to start looking a little nasty. Will soak it overnight and give it a good shot of compressed air in the morning and hopefully I'll be able to come back here tomorrow and say it purrs like a kitten and no more squirting gasoline.... either that or you'll hear a story about a Syracuse man who's snowblower exploded and wiped out half the neighborhood. Thanks again... JF

Wow, that is amazing that it was the same exact problem that the Uncle had (also in Upstate NY) the same week, losing the float pin on the floor!  Too funny.  Good luck with turning off the choke next.  I'll have to be learning all this stuff soon, snowblower is brand spanking new for the moment, but I need to learn how to take care of it.

-dan

Don't forget the copper wire in every hole you find.  Also, some holes in the venturi (carburetor throat) are so small they're barely visible.  They are usually the slow speed orifice.  Look closely into the venturi to see if there's a small hole that needs cleaning.  The diagram should also help you find the fuel circuits.   If you clean the carb properly, the float level is properly adjusted and the float needle seals as it should, the carb should work fine.  Be very gentle when working with the float and float assembly.  If it's correctly adjusted, it should go right back in and work fine.  In order to prevent future carb problems, it would be wise to install a small  in line fuel filter. 

Hey Borat -

Sounds like you work on quite a OPE equipment ....
By chance, own or use a ultrasonic cleaner ?

I've been looking at a couple made by Crest.
If you know of any other brands I should be looking at, wouldn't mind some recommendations...

chefwong wrote:
I do a lot of small motor work but I can't help you with your request. 

My hobby is rebuilding/restoring/performance enhancing old two cycle Yamaha motorcycles.  I do plenty of engine/carb work and I don't rely on anything but very thin wire, WD-40 and compressed air. No sonic devices and no more miracle cure additives. 

 I own eighteen pieces of OPE, 7 motorcycles, 2  ATVs, 1 snowmobile and 3 outboard motors.   All of which I maintain myself.  I also fix friends and neighbours OPE. 

Carburetors are easy to work on provided it's not a plastic model that cannot be disassembled.   Personally, I don't subscribe to anything but the simple methods I've already mentioned.  There's no easy way to clean a carb and be sure it's done right.  It has to come apart and every fuel passage confirmed cleaned.  If you want to save yourself a world of grief, save the money you'd be spending on an ultrasonic cleaner and buy some in line fuel filters.  Best bang for the buck for any fuel system.

Can of Berrymans is my current tool of choice. Definetely try to avoid any cleaner that says it's 50 state approved.  Just looking for a xcuse to add another toy to the shelf ;-)

if the carb runs on full choke only u might be able to get away with just cleaning it as borat described which works well for a good portion of the time and sometimes thats all thats needed, although in my experiences with carbs that run very poorly is they need to be soaked in a carb solvent (not a carb spray) l use "kleen flow" this stuff works amazing its pretty prices at about $60 for a 4L jug (napa stores sell it)  but a must for doing a proper carb rebuild in my pinion, trust me u wont be disappionted. l usally soak the carbs for at least 24hrs. and l ALWAYS replace the fuel line and filter, if theres no fuel filter then add one its very important and its super cheap insurance!

it may seem like alot to spend to repair your carb but for example if a customer needs a carb rebuild that requires it to be soaked l charge $50 + the cost of the carb kit. thats just to give ya a rough idea of what shops may be charging and thats on the the cheaper end of things.

now to the carb "squirting" gas out the tiny hole that would suggest to me that the carb is flooding in some way??

Day 2 - The Saga Continues --- Am sure those of you who are experienced at successfully and quickly repairing these kind of issues will have a laugh out of this...and this may serve as a good example of the things that often can and will go wrong for the person who "thinks" he can fix it. Have decided first, that the the gasoline "squirting" out of the tiny vent hole was caused by my failure to realize that the needle(?) attached to the float that cuts off the chamber leading to the vent hole was missing. A silly error on my part. I noticed yesterday afternoon on putting everything back together (sans needle) that pushing the primer bulb caused more gas to squirt out the side. An ah ha moment. Still I hadn't realized the needle was not re-installed as it should have been... but when I pulled the starter cord it roared to life on the first pull...sounded nice and smooth...but I still had an issue of leaking gas.... and near the exhaust...so this was a no brainer. Shut down or blow up. I decided the best advice, considering the fact I always had to keep the choke at "full" in order to run without a problem... that I would do as Borat suggested (loved your movie btw ;-) and take the whole carb assembly off the machine and soak for 18-24 hours. My first mistake in this process - not removing the rubber gasket that goes between the carb assembly and the bowl. Did not realize that the I SHOULD have done this. This morning when I looked in the can where I had the carb soaking in spray carb cleaner** (perhaps a NO NO too) I sadly discovered that this rubber gasket had expanded to about 1/2 again it's original size likely as a result of being in the spray cleaner. It has since shrunk back "almost" to it's former size...but "think" I'll likely have to get a new one (hope that isn't going to be a major challenge). ...............sooooo...while I feel I've made progress...and those Syracuse snows continue to fall...I've not given up as I'm sure I can win this battle...though I have had a few "Oh noooo" moments with this effort. ....but as I write this I now find I'm having great success in shrinking that gasket back to its original size. How? I've place it under and about 3 inches away from a bright halogen desk lamp to heat and shrink. I've just got the gasket to fit in the carb bowel and it looks like this "IS" going to work. Wow ...and Whew! To all of you who have given me advice on this problem. A BIG thank you. It's surely been appreciated and I hope that my experience with this will also help someone along the way if they have a similar problem. Now, here's hoping I get this all back together and live happily ever after. Stay tuned. Jack F

I don't understand the need to soak a carb overnight in expensive carb cleaner if all passages, jets and orifices will be physically cleaned with copper wire, blown through with WD-40 and then compressed air.  If I soak a carb in anything, it's usually just inexpensive paint thinners (Varsol) and the reason I do that is to get grit and grime off the exterior of the carb.   I wouldn't spend $60.00/gal on  carb cleaner.  Not when the carb can be cleaned for next to nothing. 

Yo  JackFlan:

 I applaud and encourage your willingness to fix your OPE.   If obtainable, having relevant diagrams and "how to" information available prior to doing the job will go a long way to make things easier.

Personally, I get great satisfaction from fixing stuff.  The absolute best reward is fixing things without having to buy anything.  I love to fabricate and innovate.  I like to improve the machine, not just fix it.   Anyone can do remove and replace mechanics and sometimes, you have no choice but to buy a replacement  part.  I do a great deal of maintenance and repair out at my camp in the bush.  It's 60 miles from civilization and lots of dirt road.  When something breaks out there, it's a looooong  way to the hardware store.   I'd say that 90% of the time I can make a fix with what I have laying around. 

Many people think they have cleaned their carb by pulling the float bow and flushing it out or letting it sit overnight in carb cleaner.  It's a start but the carb may not be not certainly cleaned.  Jets and needles must be pulled, inspected and cleaned.  The orifices and galleries that feed the jets must be know to be clean.  Air passages must also be known to be clean.  Due to the minuscule size of some orifices, it's difficult to establish that passages are clean but I look for WD-40 spraying  out the holes for my first clue.  Then I use the right amount of compressed air to blow through them to confirm that they are clear.  I use a pointed rubber tipped fitting on my blow gun which allows me to press it into air and fuel entry holes, then  I hold my finger near the exit orifice to confirm air is passing through.  I don't use too much pressure for testing because it's easier to control the air source.  I've never met a carb I couldn't fix and I've seen a few of them.

 

SUCCESS!!! 3 Cheers to ALL of you! This 30 year+ Ariens 5hp snowthrower is now running like new! Started on the first pull and now literally diving into the snow. Loooook out!!! I have done as recommended in previous posts...and ran into a few issues along the way and noted above, but in addition to the good cleaning I've also now installed a new gas line and added an inline filter. A BIG THANK YOU from snowy Syracuse to all of you who offered your assistance. Excellent help. Regards... Jack F

while in 95% of carbs u cant clean every passage way its impossible, the high speed circuits can usally be cleaned with a piece of wire or what not, but its near impossible to clean the low idle circuit, and lm speaking from experience on what works from experience,  l would say l rebuild give or take 100-150 carbs a year, and with that said not every carb needs to be soaked but l would say that 75% of carbs benifit greatly from soaking them and some of them thats the only way to clean them. 

what l have found after soaking a carb thats adjustable is the carb setting change back to the standard 1.5 turn high / 1.25 low and they run perfect. so for example yesterday l rebuild a carb on a 1977 tecumseh motor 10 hp, when it came in it would only run on 3/4 choke and it wouldn't idle at all. the high was set at 2.75 turns out and the low 3.5. if l tried to change the setting at all the machine would even run. now the only thing l did was soak the carb for 24 hrs and install a new needle and seat and carb bowl gasket, when i assemble it back on the motor i set the high to 1.5 and the low to 1.25 and the machine runs and blows snow 2ft deep without missing a beat with no further adjustment.

and yes l would agree $60 for a 4L jug of carb clean is expensive but it works, and l can use that 4L jug for a hole year probally longer if l wanted but l buy new stuff once every a year. and l charge $50 + parts for a carb rebuild so its pays for its self on the first repair.

I've never had a carb that I couldn't clean with wire, WD-40 and compressed air.   Every carb that I've cleaned ran perfectly afterward also.  People can choose which method they prefer to use.  However, if it can be done with minimal to no expense, why spend money unnecessarily. 

I've never had a carb that I couldn't clean with wire, WD-40 and compressed air.   Every carb that I've cleaned ran perfectly afterward also.  People can choose which method they prefer to use.  However, if it can be done with minimal to no expense, why spend money unnecessarily. 

lm not completely in disagreement with what u said, l just think that with as many carbs as l do every year l come across more carbs that are in pretty rough shape, and for me soaking them works the best, but everybodys got there own way of doing things and whatever works and gets the job done is all that counts.