# Basic carb questions - Craftsman 247.88720 Single stage snow thrower



## beardown34 (Jan 22, 2014)

Hello all,

I'm a small engine newb so I'd appreciate any detailed help you could give me!

I bought a used snow thrower -- Craftsman 247.88720. 21" clearing, 4 cycle, 179cc engine. It worked "OK" but wasn't throwing snow very far and was clogging all the time. I changed the oil, and replaced the spark plug, shave plate, auger paddles, and auger belt, and now I'm satisfied with how it throws snow.

Of course then I went to clean the carb fuel bowl, and now I have gas leaking from the carb. It only leaks when I tilt the machine, and does not leak when the machine is just sitting still. It's not a furious leak. Just a few drops, but enough to annoy me. My guess is I need a new bowl gasket, although to be honest my current one doesn't look like it's in very bad shape. I think the gasket for the fuel bowl nut is a little worn too. 

Anyways, Sears Parts Direct says they don't sell just the gaskets, so I bought the entire carb repair kit -- part # 951-12712 (link here). 

I was hoping to find some answers to what I think are probably simple questions.


*1) What is the black piece, and where does it go?*




















*2) What are these two gaskets for? I'm guessing one is for the bowl nut, but which one? And what's the other one for? The one on the right is a little smaller, if it isn't clear from the picture.*











*3) When I put the needle and clip onto the float, does it matter which way it goes on? Look closely in the picture -- does it matter if I orient it like the middle picture or the picture on the right? I've read that you should point the open end of the clip towards the choke, but there is no open end on my clip.*











*4) I don't know if I'm going to mess around with the emulsion tube, but assuming I try -- can I get it out without actually pulling the carburetor out of the machine? Meaning, if I use a Phillips screwdriver and remove the main jet, will I be lucky enough that the emulsion tube will easily fall out? Also, does the emulsion tube go in as it's oriented in the picture below? *











*5) PS -- anyone think it's weird that this carb rebuild kit didn't come with a new needle seat? I guess I'll have to just hope that the needle seat isn't the problem. Unless of course that black piece in question #1 is the new seat...*


Thanks in advance. If anyone remembers back to when they were first learning about this stuff, you can imagine how daunting this all can seem.


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## td5771 (Feb 21, 2011)

Before I forget I am about to put a new carb on the same machine, You should put a fuel filter inline between the tank and carb. The one I have here has none. sometimes there is a permanent screen in the tank but judging by the junk in the carb here I doubt it.

Anyway, 
1- the black plug may be for a different carb. the kit you bought cover 5 or more different brands the use a similar or same motor and who knows how many different carbs. look around after you disassemble it. you wont be able to miss something that size. If I remember correctly you will see it on top of the carb going staigh down into the carb. To be honest the information available on these new carbs is terrible. I dont actually know what its for. I have only done 1 or 2 so far.

2- different gaskets for different bowl bolts (different carb)

3- When the float and needle are in the carb the needle part that rides on the float does not ride that close to the hinge. Either way is fine just ensure no binding and free movement for the needle in and out of the carb.

4- If you dont change the emulsion tube you might as well not rebuild the carb. remove the jet with a flat head screwdriver, put the snow blower in the operating position and the emulsion tube will most likely fall out. otherwise wedge a toothpick in the center hole and pull it out. remember gas will pour out if you put it in the operating position.

5- The older carbs use a metal needle and need a rubber seat. new ones have a rubber tip and the seat is machined into the carb.


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## Shryp (Jan 1, 2011)

1. Low speed jet. You have to remove the throttle stop screw to pry it out.

2. Could be bowl nut and drain plug.

3. No idea. The open end towards choke is for Tecumseh carbs and those are definitely different looking.

4. Emulsion tube should come out fairly easily with the carb still attached. Usually a couple taps will knock it out. Failing that if you can see the choke / air intake a screwdriver can push it down as the tip sticks up into the air flow.

5. The Tecumseh's have a replaceable seat. Those clone engines do not because the tip of the needle has the rubber right on it.

If you want more help you can look on youtube for videos of cleaning Honda carbs. They should look the same as yours, although those generally use o-rings instead of the flat gaskets you are showing.


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## nt40lanman (Dec 31, 2012)

2. Could be spare for a different application.

3. Try it and make sure the clip doesn't bind against the float. That's what's important.


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## beardown34 (Jan 22, 2014)

td5771 said:


> Before I forget I am about to put a new carb on the same machine, You should put a fuel filter inline between the tank and carb. The one I have here has none. sometimes there is a permanent screen in the tank but judging by the junk in the carb here I doubt it.


That's a great idea, but how? And is there room? 

I actually bought a fuel valve to install, but realized that the fuel line isn't easily exposed (not without removing some of the shroud). I'm just not sure how much room there is under there to install a fuel filter and/or shut off valve.


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## Shryp (Jan 1, 2011)

beardown34 said:


> That's a great idea, but how? And is there room?
> 
> I actually bought a fuel valve to install, but realized that the fuel line isn't easily exposed (not without removing some of the shroud). I'm just not sure how much room there is under there to install a fuel filter and/or shut off valve.


One thing of note is the clones I have seen use a smaller fuel line than the normal 1/4" that is common on the Briggs and Tecumseh engines.


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## beardown34 (Jan 22, 2014)

Shryp said:


> 1. Low speed jet. You have to remove the throttle stop screw to pry it out.
> 
> 2. Could be bowl nut and drain plug.
> 
> ...


You are correct -- a google search shows that you're right about #1 -- low speed jet. I don't think it is easily accessed on my carb without pulling it off the machine, so I probably won't mess with it. 

After this polar vortex passes and the temperature is a little more moderate, I'll take off the fuel bowl again and see if you're right about #2, that one of the small gaskets is actually for the drain plug. That would be a great and easy explanation! I'll also check out the emulsion tube too, and hope that it falls out as easily as you guys suggest.

As for the needle seat, I thought the seat in my carb looked brass/goldish, but I will need to check to be sure. I'll get back to you all.

BTW, stupid question, but how do I know what kind of engine I have? B&S? Tecumseh? All it says on the Craftsman parts diagram is Engine - zs365-sub.


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## Shryp (Jan 1, 2011)

Looks like a Chinese Honda clone engine. Looking at the carb diagram you do have the bowl nut plus a drain plug. My guess is that is why you have 2 bowl nut gaskets, one for the drain plug.

http://c.searspartsdirect.com/lis_png/PLDM/P0909069-00003.png


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## beardown34 (Jan 22, 2014)

Shryp said:


> Looks like a Chinese Honda clone engine. Looking at the carb diagram you do have the bowl nut plus a drain plug. My guess is that is why you have 2 bowl nut gaskets, one for the drain plug.
> 
> http://c.searspartsdirect.com/lis_png/PLDM/P0909069-00003.png


You are 100% correct -- I'm guessing the two gaskets in my carb kit are parts 141 and 142 in that diagram. Of course Sears in their supreme helpfulness left out parts 133 to 143 in their diagram legend!


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## beardown34 (Jan 22, 2014)

Just a followup -- 

1) I used the new fuel bowl gasket and the leaking stopped (hooray!)

2) It was a little harder than I had anticipated getting the main jet out. It unscrewed easily enough with a Phillips screwdriver, but then stopped unscrewing when it reached the threads that the fuel bowl nut screws into. Fortunately there was a little pin hole just to the side of where the the main jet was, and I was able to use a toothpick to slowly push it down and out.

Then the emulsion tube did not drop out easily even with a little tapping, so I ended up putting a Torx T6 screwdrive up into the old emulsion tube and was able to get it out that way. Installing the new emulsion tube and main jet was easy and uneventful.

3) Regarding the two red gaskets -- the slightly larger in diameter one was the gasket for the bowl nut (the original gasket was literally falling apart), and the smaller diameter one was a gasket for the fuel plug (the original one seemed to be in good condition).

4) ARGHH -- the new float from the carb rebuild kit DID NOT FIT! Can you believe it? 

The silver part of the float, where you clip the needle into and what you run the float hinge pin through, was too wide for the existing opening. I tried every which way and it wouldn't fit. This is frustrating and I'll have to call MTD about this. Fortunately, even with my old float and old needle, there is no gas leak so these parts were apparently still fine.

5) I did not use that black low idle jet I asked about in my first post. I didn't see any place for it when I took off the fuel bowl and approached the carb from below, and do not have the confidence to dissamble the carb any further to find it. 


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