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Discussion Starter #1
I have a Craftsman model 247.88957 with a ZS365-SUB engine. The engine surges at anything above almost full choke. I have dropped the float bowl and cleaned it out, pulled the float and blew carb cleaner up thru the jet. I have fresh gas in the tank with Seafoam. It still surges. I think it is running lean and needs a mixture adjustment. But I cannot for the life of me locate any mixture screw anywhere on the carb. I have pulled most of the shroud, turned it upside down, rooted around with a light and I see nothing that looks like a mixture adjustment screw. Please educate me. Where is it?
 

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If the bottom of the bowl on the carb is just a nut then it is a fixed jet carb, I am seeing if I can reference the carb to see if a adjustable needle version is still available that would work, There are some still made that fit the older tecumseh engines to have adjustable carbs but not sure yours does. However it may NOT be a carb issue, The surging and lean condition sounds like it could be a air leak some place, A friends log splitter is doing the same with a new carb on it but I have not had the time to chase down the issue. But try some new gaskets and make sure everything is tight mounting the carb, It may be as simple as some grime falling in while putting the carb on but def sounds like a air leak some place.
 

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welcome to the forum wade ! admittedly not familiar with your machine, but most modern units have fixed jets. you cant tune any restrictions out, nor can you tune any air leaks out. clean the carb , then clean it again. if that doesnt help, there are some cheap china replacement carbs that members here have very good luck with.
 

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Discussion Starter #4
Thank you for the prompt response. All it has on the bowl is a drain screw and a mounting bolt. So your "fixed jet" theory may be it. (Dumb design IMHO). Of course the Craftsman manual is useless. The air leak idea is interesting and I will look into it and let you know. Thank you again.
 

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No adjustments allowed on the carbs per the out of control U.S. EPA.:frown:
 

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This machine has a Honda clone on it. The carbs tend to get clogged really easy on these. I've started opening up the jet on them, just to counter act it being lean from the start. And the fact they clog easily. Your probably going to have to take the carb off and really clean it good. If that doesn't work, new carb is next step.
 

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The prefix 247 says it's an MTD build. They use the Powermore engine. There is a lot of crap to take off to get at the carb. You can try and get the main jet out if you're fingers aren't already frozen:icon_smile_big:
If you have the bowl off, look up into the center stalk where the bowl nut screwed out of with a good flashlight. You should see the main jet and it's slot for a flat head screwdriver. Use the biggest one that will fit up and not touch the threads (I have cheapo HF screwdrivers and grind off the flaring to make them have no "hump" near the tip). Unscrew that jet and it should drop right in your hand IT'S SMALL so maybe put a sheet under where you're working. Above it will be the emulsion tube that hopefully will fall out also (tapping the carb may release it or use small pick). You can take a bread tie wrap and chase the main hole and the little ones all over the emulsion tube. There is also a pilot jet friction fit in a plastic holder on top of the carb usually under a black screw to adjust idle speed. If you can get off the shrouding to see it, it's very apparent. You can pry it out with a small screwdriver and chase that hole with a bread tie also. Put it back try it. I've probably had 4 out 5 clear up just doing this. If not you can get the carbs for around $25 MTD part 951-10974A just google it.
https://www.partstree.com/parts/mtd/snow-blowers-snow-throwers/247-88957-31bm62ee799-craftsman-snow-thrower-2009-sears/engine-assembly-365-sub/
It is set up very similar to this Honda carb for reference only:
Disassembly, Cleaning and Repair of Carb 16100-ZF6-W10 on Honda GX390 QA2X Engine
 

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Good advice above...

I once had a small engine that never did run right and I had that thing apart at least a dozen times.
Ran it through ultrasonic cleaners, rebuilt it, cursed at it and eventually bought a new carb.
Been running perfect ever since (2.5 yrs)
If a new carb is cheap, save yourself a headache and just replace it.
 

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ALOHA from the paradise city.:smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027:
 
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