snowblower engine problems

Actually carb problems I believe. I have an older Ariens 6hp snowblower. At first I could not get the thing started after not having been used in quite some time. I disassembled the carb and cleaned everything out and got it to run good. Adjusting the carb as taught in a small engine repair faq I found online.
Anyway, what happens is the motor runs great for say 15min or so and then it starts to surge. It will start to die, the govenor linkage moves, the engine speeds up and then the process repeats. The first thing I noticed when this happened that if I close the choke the engine speed will pick back up. But obviously after the motor is warmed up I shouldn't need the choke....
So I adjust the mixture screw on the bottom of the carb a little bit it solves the problem for about 5 min. Then it will start to die again after the 5 min. and I have to adjust that mixture screw again. I checked and the screw is not turning on its own. After happening several times the screw was almost adjusted all the way in when I finished my driveway today.
So what causes the mixture to lean itself out over time?
Thanks,
Chris Roberts
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maybe an air leak, go over your work on the carburator ,gaskets, fuel line
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You have a blockage in the carb still. Or a vacuum leak between block and carb.
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Flat gasket between carb adn engine. That's a good thought.... I'm having some odd problems with my smowblower also. Makes me wonder. Might be same thing.
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Christopher A. Young
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Look for a fuel filter that may be blocking up. Another thing that seems unrelated but caused some very erratic running of my snowblower was that the oil level was too high. Tecumseh (sp) engines are very finicky when it comes to the oil level.
If that is what you have check the oil level and if it is past the full line, even just a hair, take some oil out and also replace the spark plug while you are at it.
I am guessing like the others though that you are experiencing a fuel blockage from one source or another.
Are you using fresh gas?
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Thanks for the info guys. I am thinking maybe I should take the carb apart again and clean the sucker out again. Fairly simple to take apart..... I am using fresh gas.
I was just curious as to why it would run ok for a while and then start to die until I adjust the mixture screw, then run fine again for a while and start to die again until I repeat process.... Maybe touching the mixture screw helps with the blockage?
Thanks a bunch!
Chris

and
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On Fri, 19 Dec 2003 21:01:09 GMT, "Chris Roberts"

One thing that may make sense with your description is a gasket that is loosing its seal after the engine gets warm. Some component may be changing its dimension?
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Chris,
I have a snowblower that's in the same boat yours was (buggered up carb). Can you please post the link to that small engine FAQ you mentioned? Thanks.
Chereo!

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Hey bro, I believe this was the guide I was looking at:
http://www.repairfaq.org/sam/lmfaq.htm

snowblower.
faq
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after
screw
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I am confused by your description. Closing the choke richens the mixture, but turning the mixture screw in leans it. If your mixture is getting leaner check for inadequate fuel flow caused by plugged filter or plugged tank vent. If it is getting richer check for carburetor flooding caused by worn or dirty needle and seat or by binding float. Check for any dimple where the needle contacts the float arm. Also be sure your fuel is fresh.
Don Young

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Hehe, I was thinking the same thing after I posted it. But the speed definitely picks up big time when I choke it (after it has been running for some time and starts to die) yet at the same time I *was* turning in the mixture screw and it was running better. Maybe there is some blockage with that needle that cleans itself out temporarily when I turn it?
The first time I got the motor running it was running really rough and about to die. I went down to adjust the screw and all I really did was touch it - I didn't really move it and it started to run fine. So maybe thats where the prob is? I will take a look : )
Thanks,
Chris

snowblower.
faq
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after
screw
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Tank vent clear?

in
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