Leaking needle seat in B&S carb

T

ttimtucker

Active Member
Hi, I have 2 questions.

1) I've recently cleaned 2 B&S carbs in my ultrasonic cleaner using water and a generous splash of Simply Green. After cleaning, the needle seat would not seal properly and I had fuel leaks. I'm not sure whether the first carb leaked prior to cleaning since I never tested it, but I'm sure the second carb did not leak prior to the cleaning. Does anyone have advice/knowledge on whether Simply Green does something to the rubber seat that would prevent proper sealing?

2) I'm trying to find a replacement needle seat for the second carb mentioned above. It comes from a B&S 123K02-0258-E1 engine. Based on various web sites I believe the B&S part number for the carb is 498170. The only markings on the carb itself are "6150N" and "3152". I'm not having much luck finding replacement seats. How likely would it be that some other carb seat would work in this carb? Are there many different sizes that these seats come in?

Thanks for any advice.
 
Can't answer the Simple Green as I never it, just have used Dawn.
replacement needle and seat is PN 398188.

When installing the seat make the side with groove faces inward or the new seat will leak.
 
Always pull any rubber or silicone parts prior to any ultra-sonic or boiling cleanings. Most of the time they need replaced anyway.
 
slomo said:
Always pull any rubber or silicone parts prior to any ultra-sonic or boiling cleanings. Most of the time they need replaced anyway.
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Why on Ultrasonics. I have never had to and many times I even the paper gaskets attached. Besides you can't remove the rubber check valves in 2 cycle carbs.
 
StarTech said:
Why on Ultrasonics. I have never had to and many times I even the paper gaskets attached. Besides you can't remove the rubber check valves in 2 cycle carbs.
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Because I own my equipment not just work on them like you shop guys. I pull all rubber/plastic parts and inspect. Carb bowl gaskets usually get tossed.
 
slomo said:
Because I own my equipment not just work on them like you shop guys. I pull all rubber/plastic parts and inspect. Carb bowl gaskets usually get tossed.
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Don't be assuming things...I multiple pieces of equipment myself as I have 6 acres to care for. Both 2 and 4 cycles are part of this inventory. Depending how long a piece has sat unused is if the carburetor has to be clean. Since my property is also a test for repaired equipment some my equipment may sit a lot longer than it should.

And of carb bowl gasket do get tossed most times

And like to know you are pulling all those 2 cycle carburetors check valves. I never had to besides most are non-replaceable.
 
I have not had success eliminating the leak. I've installed several new seats (part number 398188) and test with 3 PSI pressure and there is always a slow leak. See photo for my test setup (you can also see the tool I'm using to remove and insert the seat). If I apply a tiny amount of pressure on the float with a finger, the leak stops. As an additional test, I installed one seat using a small amount of gasket sealer around the circumference to see if the leak might be coming from around the seat edge, but that made no difference. So I'm concluding that the leak is coming from the interface between the needle and the seat. I've examined the needle under a microscope and can see no imperfections (but I have not replaced the needle). I'd love to fix the OEM carb, but the I don't like the idea of throwing money at different seat and needle kits, when I can get a clone carb for $15. Any more ideas?
 

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