Carburetor Rebuild

Cornhead386

New User
I will probably get taken to the cleaners for this one but I am trying to rebuild my 8N carb. Things were going well until I tried to remove the main jet. The top of the brass broke off the jet. I unscrewed the brass screw on the bottom of the carb and drilled out what I could without damaging the threads. Then hit it with a punch thinking (read: hoping) it would break apart. It work like a charm…for half of it. The other half is still in there. And now it is too far eroded to get with the punch. Any ideas or experience that can save me or is my carb shot?
 
I will probably get taken to the cleaners for this one but I am trying to rebuild my 8N carb. Things were going well until I tried to remove the main jet. The top of the brass broke off the jet. I unscrewed the brass screw on the bottom of the carb and drilled out what I could without damaging the threads. Then hit it with a punch thinking (read: hoping) it would break apart. It work like a charm…for half of it. The other half is still in there. And now it is too far eroded to get with the punch. Any ideas or experience that can save me or is my carb shot?
Are you dealing with the seat of the inlet needle and seat? If NOT there's really no reason to remove jets for a basic carburetor tuneup. Or, what, specifically did you break?

This MAY be an example of "If It's
not broken let's break it 'til it is"!
 
Are you dealing with the seat of the inlet needle and seat? If NOT there's really no reason to remove jets for a basic carburetor tuneup. Or, what, specifically did you break?

This MAY be an example of "If It's
not broken let's break it 'til it is"!
sure sounds like it.
 
I will probably get taken to the cleaners for this one but I am trying to rebuild my 8N carb. Things were going well until I tried to remove the main jet. The top of the brass broke off the jet. I unscrewed the brass screw on the bottom of the carb and drilled out what I could without damaging the threads. Then hit it with a punch thinking (read: hoping) it would break apart. It work like a charm…for half of it. The other half is still in there. And now it is too far eroded to get with the punch. Any ideas or experience that can save me or is my carb shot?
As long as that passage is clear, you can live without the main jet. It is also known as the maximum fuel limiting jet. That is what it does, limits the maximum amount of fuel that can be drawn through the carburetor. The main adjusting needle and it's seat is what meters the fuel normally.

That said, if you drilled it with the proper tap drill size for a 8-32 thread (#27 .1440), you should be able to remove the brass remaining in the threads with a 8-32 tap. A spiral point tap is best of course as it has clearance for the chips to fall free, but a regular tap will work if you are careful.
If you drilled with a 1/8" drill, there would be too much metal left to get a tap through.

Had a carburetor once that someone drilled out the main jet with an oversize drill leaving no threads in there. I just put it together without the main jet and the tractor runs fine.

Best of luck.
 
Are you dealing with the seat of the inlet needle and seat? If NOT there's really no reason to remove jets for a basic carburetor tuneup. Or, what, specifically did you break?

This MAY be an example of "If It's
not broken let's break it 'til it is"!
I broke the jet itself. I realize that now (y)
 
As long as that passage is clear, you can live without the main jet. It is also known as the maximum fuel limiting jet. That is what it does, limits the maximum amount of fuel that can be drawn through the carburetor. The main adjusting needle and it's seat is what meters the fuel normally.

That said, if you drilled it with the proper tap drill size for a 8-32 thread (#27 .1440), you should be able to remove the brass remaining in the threads with a 8-32 tap. A spiral point tap is best of course as it has clearance for the chips to fall free, but a regular tap will work if you are careful.
If you drilled with a 1/8" drill, there would be too much metal left to get a tap through.

Had a carburetor once that someone drilled out the main jet with an oversize drill leaving no threads in there. I just put it together without the main jet and the tractor runs fine.

Best of luck.
Thanks for the idea...I will give that a try.
 
If it an original carb that is cast iron and all else fails if you have a an oxy/acetylene torch or know someone that has one you can just melt that jet out of there.
 

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