Repeat Carburetor Problems

A

Alex Ethridge

Active Member
Briggs Engine Model 31S877 0001 G1 160418ZD, OEM Carburetor 594593, Needle 594868
I'm sure this mower hasn't more than a hundred hours on it and I have not used ethanol fuel since replacing the carburetor a year ago with a genuine OEM carburetor.

I replaced the carburetor less than a year ago due to flooding. Now, the replacement is doing the same thing after using it through last summer and using it twice this year. Float level checks OK. I thought I might try replacing just the needle but got sticker-shocked.

Any users here have suggestions short of a new carburetor?

Any idea where I might find after-market needles that will fit?

I remember in the 1980s, I got after-market needle-and-seat assemblies from Prime Line at deep discount, ten or a dozen in a pack for about what I would pay Briggs for just one, and they were good stuff but I can't find anything like that there today.
 
it's possible your fuel lines could be coming apart or you might have debris making it past the filter, that can cause the needle to stick open and flood out. It doesn't take a very big piece at all.
 
Scrubcadet10 said:
it's possible your fuel lines could be coming apart or you might have debris making it past the filter, that can cause the needle to stick open and flood out. It doesn't take a very big piece at all.
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Yep, debris in fuel can lodge between needle and seat and cause issues. You can install a fuel shut off valve and use it every time you are finished mowing. You can also tap on carburetor bowl with the handle of screwdriver to often get needle and seat to seal.
 
Are you saying that fuel gets into the oil or it runs flooded or ???

I would think about testing the carb"s needle and seat with pressure such as a mityvac or blood pressure bulb instead of just throwing new carbs on. (lots of You tube info about how to do such.

You should replace your fuel line and also install a Briggs or Stens fuel filter and manual cut off valve. Do not use china stuff. Use the manual cut-off each time you are not running the engine.
You are most likely also now using China Carb replacements. Best to try and fix your OEM carb.which was probably a Nikki.(If a Nikki type the gas can bypass the needle seat when the upper gasket goes bad. At first it's the needle seat and then when you take it apart and repair that and do not replace the upper gasket it still leaks usually and this can be confirmed with a carb pressure tester.
 
Thanks for reading and the suggestions.

To answer the questions: Mine is Ruixing as that name is in relief in the casting. Replacement is OEM, cost $107.40 when I bought it a year ago. So far, no Chinese junk. Before I replaced the original, I tried disassembly and cleaning but no change, belching gas out the intake on the rare occasions that it would finally start, then would flood and quit. It already has as OEM filter and OEM shutoff valve from Briggs when new.

I don't have a lot of time today to work on it but will try and get back here and post my result.

By the way, no fuel in the oil.
 
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Never heard of pressure testing, don't know what it is or how to do it.

Update: Found it on YouTube. Now I understand.
 
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I just turn it upside down and try to blow through the fuel inlet , you should not be able to push air through it , then turn it right side up and do the same thing , air should flow easily, if pass all test , take apart and look at the jet , pull and clean , you should be able to see the hole all the way through with no obstructions visible. Small particles can disrupt fuel flow
 
I suggest you also check the valve adjustment to make sure they are not too tight and allowing compression past the intake valve and seat. Valve adjustment is critical especially after initial break-in.
 
Will do.

I let the mower run for hours at night until it emptied the tank. Today, I put in gas from the same container as before, wet the air cleaner with starting fluid and it started right up and ran perfectly while I cut the back yard. I parked it, let it sit for about a quarter minute and it started fine again, but with one pop, and again with another pop.

Just guessing, maybe something cleared the needle once the float had dropped the needle to an empty-bowl position. Now that I have the grass cut, maybe I'll have time to check the valves and run that needle pressure check. I ordered a cheap BP checker from e-bay yesterday.
 
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