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Old Yesterday, 12:10 PM   #1
popeyestruck
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carb leak

I have a small leak where the brass fitting for the fuel line goes into the carb. Not too much just enough to wet the area. I think its a 1/2 female to 9/16 male . Can I put a nylon or copper washed on the fitting where it connects to the carb? Just trying to stop the leak
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Old Yesterday, 12:54 PM   #2
leegreen
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Re: carb leak

you have a Rochester B ?

If I remember correctly the fuel line itself has a flare, so if it is in good shape might just need tightening. The flare goes into a fitting that threads into the card with a pipe thread, which should get some thread sealant. Paste sealant is better here, if you use tape be careful to not have any extend past then end of fitting where is might shear off and get inside the carb.

newer carbs would have a gasket.

Picture of the carb / leaking spot?
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Old Yesterday, 02:56 PM   #3
popeyestruck
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Re: carb leak

I'll try some sealant. Thanks
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Old Yesterday, 06:10 PM   #4
mr48chev
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Re: carb leak

You want to be careful with sealer around fuel lines. I would figure out what the issue is and correct it.

I'm still digging for Rochester B info as the photo I had was a BV and not a B.

If it is leaking where the pipe fitting goes into the housing you could use a minimal bit of sealer or thread tape. Bare minimum.

If it is where the tube seats in the flare you can try tightening the fitting (use two wrenches). I would pull it apart and check the flare over real close though and make sure there is no dirt in the seat.

Those images from this pfd that has excellent instructions in it. https://www.carburetor-parts.com/ass...r-b-manual.pdf
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Last edited by mr48chev; Yesterday at 06:37 PM.
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Old Today, 04:45 AM   #5
popeyestruck
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Re: carb leak

Its leaking where it goes into the carb body. I didnt realize it was a pipe fitting. Its bottomed out with no threads showing
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Old Today, 10:58 AM   #6
dsraven
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Re: carb leak

if the adapter fitting is leaking where it screws into the carb it could mean that it has been screwed into the carb body too far in order to get a seal. pipe threads are a tapered thread so it is like a wedge. the carb body is aluminum so if it were me I would check the carb body for any tiny cracks caused from the fitting being wedged in too far. the fitting itself is a fairly common one so you could source a new one before doing anything, so you have it on hand if need be, then unscrew the flared fitting and get the supply tube out of the way, then unscrew the adapter fitting from the carb, check for any small cracks in the carb body and for any bad threads in the carb hole. if,none and the carb end of things looks all good, check the adapter fitting threads and look for any cracks etc. check the flared connection for distortion or anything that may cause a leak. if all good decide if you want to re-use the fitting or install the new one, use some thread sealer on the pipe threads and screw it back in. if using the teflon tape there are different qualities of the stuff. in Canada the white stuff is generic and not to be used for any natural gas or propane fuel connections by code. there is a thicker style used for this purpose and it is either pinkish or yellowish color. I would use the natural gas teflon tape if I were to use that method. another method of pipe sealer is the thread sealant compound, or pipe dope which is a paste. some say to use it over the teflon and some say to use it all by itself. it is a lubricant as well as a teflon based sealing compound.
since brass and aluminum are both pretty maleable you might be better served to replace the brass fitting in case it has distorted by being overtorqued into the carb. the problem with doing this is that the flared fitting is also maleable and usually the sealing surface if the flare has become slightly distorted to cvonform t the brass fitting's sealing surface and vice versa. a new fitting may fit into the carb and seal well but the flared fitting may become your new leak.
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