Carb Still Leaking After Parts Replacement

[Sinfahl]

Engine model:123K02-0193-E1

Primer button type carb

I've replaced the float, needle valve, and the needle valve seat using all B&S genuine parts. From bench testing everything looks great; I test that everything seals right on the bench by turning the carb upside down and drawing a 5psi vacuum on the fuel inlet and it holds steady.

After this, I start to notice problems

1) The float doesn't sit level, no matter how far I push the seat down beforehand. It's not overly tilted like "\", but it is clearly noticeable

2)I can reinstall everything to the lawnmower and run it a few minutes and there's no leaks, but when I come back maybe an hour later the mower won't start and I start to get a steady stream of fuel leaking out the gold tube that sprays fuel after priming

3) The stream of fuel from the tube leaks worse when the gas cap is removed

 

[Tiger Small Engine]

Engine model:123K02-0193-E1

Primer button type carb

I've replaced the float, needle valve, and the needle valve seat using all B&S genuine parts. From bench testing everything looks great; I test that everything seals right on the bench by turning the carb upside down and drawing a 5psi vacuum on the fuel inlet and it holds steady.

After this, I start to notice problems

1) The float doesn't sit level, no matter how far I push the seat down beforehand. It's not overly tilted like "\", but it is clearly noticeable

2)I can reinstall everything to the lawnmower and run it a few minutes and there's no leaks, but when I come back maybe an hour later the mower won't start and I start to get a steady stream of fuel leaking out the gold tube that sprays fuel after priming

3) The stream of fuel from the tube leaks worse when the gas cap is removed

Buy another carburetor.

 

[Sinfahl]

Buy another carburetor.

So I guess they just get to a point where they'll just act up no matter what? This isn't an aftermarket carb.

 

[ILENGINE]

Was the donut valve seat installed correctly and not upside down, which can cause a different float height. Also was there carb cleaner residue in the carb when the seat was installed. Carb cleaner will make the seat swell and in some cases crumble. I am not a fan of using vacuum to check a float seat. You can create a vacuum in places were the same component won't hold pressure.

 

[StarTech]

Engine model:123K02-0193-E1

Primer button type carb

I've replaced the float, needle valve, and the needle valve seat using all B&S genuine parts. From bench testing everything looks great; I test that everything seals right on the bench by turning the carb upside down and drawing a 5psi vacuum on the fuel inlet and it holds steady.

First you don't Draw (pull) a vacuum as that just makes things seal even tighter. You pressurize at 7-10 psi (usually around 7 psi) and see if there any loss of pressure. If it going to leak it leak under pressure this what pushes the needle off seat even under flow systems. This pressure test needs to done for at least 30 minutes.

If pressure loss it can sometime be leaking around the needle seat and not where the needle meet the seat. And seems to be some defective after market seats out there this year as I done ran into a couple.

 

[Sinfahl]

Was the donut valve seat installed correctly and not upside down, which can cause a different float height. Also was there carb cleaner residue in the carb when the seat was installed.

I installed the valve seat with the ridged side facing the carb and the flat side facing the needle.

First you don't Draw (pull) a vacuum as that just makes things seal even tighter. You pressurize at 7-10 psi (usually around 7 psi) and see if there any loss of pressure. If it going to leak it leak under pressure this what pushes the needle off seat even under flow systems. This pressure test needs to done for at least 30 minutes.

If pressure loss it can sometime be leaking around the needle seat and not where the needle meet the seat. And seems to be some defective after market seats out there this year as I done ran into a couple.

Ohh I didn't know that was the distinction when testing. I wish there was more written about this.

I did use an oem seat & needle however.

 

[Sinfahl]

Here's a highly magnified pic of the seat if it helps any.

 

[slomo]

Looks like a beaver has gotten to it.

.

 

[Rivets]

In my opinion that seat is toast and should be replaced.