# Tecumseh carb leaking gas from throat



## Frostikins (Dec 17, 2020)

I rebuilt my Tecumseh carb on my snowblower. I replaced the float needle and the needle seat as well as the emulsion tube and the rubber o rings on the emulsion tube and the bowl and bowl nut gaskets. When I remounted the carb gas wass leaking out of the throat of the carb and coming out past the choke plate. I thought it was a faulty bowl gasket at first but it definitely is wet inside the throat of the carb.

The float seemed to be level when I turned the carb over. And when I blow into the gas inlet the air sound stops when I turn the carb upside down and the float levels out and seats the needle. This seems to indicate that the float needle is working.

If it's not a bad needle or seat could it be leaking past the o rings on the emulsion tube and getting up out of the bowl that way? This has got me kind of mystified.


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## 140278 (Aug 27, 2020)

did you install the tiny rubber seat with the ring up to the inside if down into the carb body if down the needle won't seat as the rubber is tapered


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## Frostikins (Dec 17, 2020)

Knowing me, it's probably backwards. I have to search for a kit that just has that seat and the bowl gaskets and try it again. That seat leaking is the only thing that makes sense.
Just to be clear, If I'm looking down into the hole where the rubber seat goes should that little ring on the end of the seat be facing up at me?


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## Jesse11B (Jan 27, 2020)

On some carbs there’s an external vent hole that can be clogged an cause leaking problems. Check out Don’s video about this problem.


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## Jesse11B (Jan 27, 2020)

Frostikins said:


> Knowing me, it's probably backwards. I have to search for a kit that just has that seat and the bowl gaskets and try it again. That seat leaking is the only thing that makes sense.
> Just to be clear, If I'm looking down into the hole where the rubber seat goes should that little ring on the end of the seat be facing up at me?


Sounds like you may have the seat upside down. The 8:00 minute mark in Steve’s video shows installing the seat.


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## Frostikins (Dec 17, 2020)

Thanks for the info captchas and Jesse.


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## Frostikins (Dec 17, 2020)

Here's the thing that's got me puzzled. If I blow into the fuel intake of the carb when it is right side up I can hear and feel air passing through the jets and openings. If I turn the carb upside down so that the float falls (to a point which simulates a full bowl) and the needle seats then I cannot hear or feel any airflow and I get back pressure from the fuel intake barb. I would think that if the weight of the float is enough to stop air pressure leaking by then the fuel in the bowl lifting the float should be enough to seat the needle also.

It's a plastic float but I'll check it for leaks. It's possible that the rising fuel level may not be enough to seat the needle completely.

EDIT: I popped out the needle seat and made sure it was reinstalled correctly. I believe it may have been upside down because the float is now at a slight angle instead of being horizontal when I hold the carb upside down, and I'm positive that I correctly installed the rubber seat. Also, the float has no gas in it.
Does anyone know the proper angle for the float or a measurement from the carb edge to the float? I notice in the Steve's Small Engine repair video above that Steve is holding the float to a more than horizontal position to fully stop the fuel flow


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## Frostikins (Dec 17, 2020)

Jesse11B said:


> On some carbs there’s an external vent hole that can be clogged an cause leaking problems. Check out Don’s video about this problem.


Thanks for that. I ran a thin twist tie wire through that hole with no resistance and I can feel air coming out of it when I blow into the fuel intake port.


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## paulm12 (May 22, 2015)

Frostkins: regarding the float angle, this doc calls out " With the carb inverted, the free end of the float should rest 11/64 inch from the body of the carb (#10). To adjust, bend the tang on which the needle sits." You can use a 11/64 drill bit to check. Most people just get the float close to level.

the site is here and has good reference info: Disassembly, Cleaning and Repair of Tecumseh Series 1 Emission Carb 640084B


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## Frostikins (Dec 17, 2020)

paulm12 said:


> Frostkins: regarding the float angle, this doc calls out " With the carb inverted, the free end of the float should rest 11/64 inch from the body of the carb (#10). To adjust, bend the tang on which the needle sits." You can use a 11/64 drill bit to check. Most people just get the float close to level.
> 
> the site is here and has good reference info: Disassembly, Cleaning and Repair of Tecumseh Series 1 Emission Carb 640084B


Great resource. I've book marked it. Thanks.


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## Rooskie (Feb 12, 2015)

As I seem to recall seeing elsewhere hereabouts, isn't it a whole lot easier to buy a carb for this engine and bolt and go? I would like to just jump to the chase and purchase new for thrifty dollars instead of rebuilding.. I was once told: Carburetor is a French word meaning, 'Don't touch it'. I've lived by those words.


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## Frostikins (Dec 17, 2020)

Rooskie said:


> As I seem to recall seeing elsewhere hereabouts, isn't it a whole lot easier to buy a carb for this engine and bolt and go? I would like to just jump to the chase and purchase new for thrifty dollars instead of rebuilding.. I was once told: Carburetor is a French word meaning, 'Don't touch it'. I've lived by those words.


Yes it is possible. I didn't want to spend the $80 for a new OEM carb so I bought a cheap after market one with adjustable jets but right out of the box it surges. I'll have to play with the adjustments to see if I can cure that. But as someone else said, there is no guarantee that the new after market carb is perfectly clean either.


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## 140278 (Aug 27, 2020)

believe it or not but that seat is really tapered ever so slightly yet will go in both ways 1 leaks 1 doesn't and won't let the needle seat and hold 
thanks to the members in here i don't rebuild them anymore either 18 bucks for a repair kit 20 for a new one makes no sense anymore esp with ethanol gas around us


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## Frostikins (Dec 17, 2020)

I wanted to update everyone. I removed and reversed the needle seat. It was upside down. Happily the leaking from the throat stopped. Thanks to everyone for all the good advice.

Incidentally, I used a method I learned on Steve's Small Engine Repair videos to remove the small rubber needle seat. I cover the port where the needle fits in with a rag and used a compressor to blow into the fuel intake. This shot the needle seat out without damaging it. The rag is important to catch the seat as well as padding your hand. The seat comes our with a lot of force and stings your palm, even with the rag. Also, after reinstalling the needle seat, I found that the float measurement was less than 11/64th of an inch and I corrected that.


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