# Problem with Briggs carburetor



## RKDOC (Jun 20, 2006)

Briggs engine model 289707 Type 0154-01. I installed a new carburetor Part # 498027. After hooking up the fuel line I noticed that the filter base was filling with gas. I clamped the fuel line off and removed the new carb. I took the bowl off and checked the needle and seat, all looked fine. Put the bowl back on and mounted the carb. I hooked up the fuel line and unclamped the line. Gas soon started running out the carb at the choke butterfly end. Why would this happen on a new carb? When I checked the needle and seat before reinstalling the carb I hooked a piece of hose to the inlet. With the carb upright I could blow into it. When I turned the carb upside down I could not blow air into the carb. To me this would indicate the needle and seat were working. I also checked for fuel in the float and could find none.

Does anyone have any ideas what would cause the carb to leak gas out like this? New carbs should work!!


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## 30yearTech (Sep 14, 2006)

Check the fuel bowl vent and make sure it's open. A plugged bowl vent will cause a carburetor to flood.


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## pyro_maniac69 (Aug 12, 2007)

its also possible that you got a defective carb, it might have a hairline crack in the housing where the seat goes, and is making its way past there


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## RKDOC (Jun 20, 2006)

Thanks 30 Year and Pyro. On this carb where is the bowl vent? Under the float there is a plate with a couple of little holes in it, The place is riveted to the housing so I can't see what uis under the plate. Where is the vent opening to the atmosphere? I would like to check for the plugged vent.

Pyro. Briggs said that if it had any crack it would not hold air when I pressure it. Do you think this is true?

Thanks for the help.


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## tommyj3 (Sep 16, 2006)

I would think there is dirt and trash in the fuel tank. It's getting in the carb and keeping the needle and seat open.


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## 30yearTech (Sep 14, 2006)

Without the carburetor in front of me, I would be hard pressed to tell you how it vents. The plate thats riveted inside covers the vent inside, there is an external outlet to let air into the float bowl, but I am not sure where to tell you to look for it. Some carburetors have a little tube on the top that a hose will attach to but I don't know if this one does.


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## pyro_maniac69 (Aug 12, 2007)

it might be a small enough leak that you don't hear the air escaping, does the float look like its formed incorrectly at all?

Also, remember to ask yourself this "does a float float?

aka, put it in some water and see if you see any air bubbles


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## Rentahusband (Aug 25, 2008)

Even with the carb upside down you should still be able to pass air through, there is not enough pressure on the needle to stop the force of you blowing. In the upright posisition the fuel causes the float/needle to create a seal. I assume the float is plastic so there is no tab to adjust the float. Is the tip of the needle rubber or metal. Being this is a New Carb I would contact who ever you got it from. Is'nt the purpose of the vent to allow air to escape so fuel will flow in. A plugged vent would cause an air lock preventing fuel from flowing. 
Dean


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## RKDOC (Jun 20, 2006)

Thanks for all the replies. I used the trick on another post about using lapping compound to clean the seat. Carb works like a champ. I talked to briggs and they will pay my time for fixing it and the second oil change because the new carb Gassed the oil.

Thanks


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## 30yearTech (Sep 14, 2006)

Rentahusband said:


> Isn't the purpose of the vent to allow air to escape so fuel will flow in. A plugged vent would cause an air lock preventing fuel from flowing.
> Dean


It does cause an air lock, but that does not stop the fuel from flowing, in fact it causes just the opposite! The air trapped in the float bowl actually holds the float down allowing fuel to flow through and flood!


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## Rentahusband (Aug 25, 2008)

Thanks for the explination 30year.
Dean


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