Fuel System: Fuel fitting sealants or ideas

[Ron Dame]

OHV Champ 6 with Carter fuel pump. The way these pumps are clocked, the outlet is about 30 degrees from perpendicular to the block, and a 90 degree brass fitting is needed to get the outlet pipe on. At least I see no other option.

Here's my problem: This is an original remanufactured pump ( ethanol safe) that works fine. I need a 90 degree brass fitting to get the outlet pipe connected. There is only one position where the outlet pipe fits, and either it's too loose and leaks, or gets so tight 180 degrees from there, that I am afraid I will crack the fuel pump if I go further. Who knows how many times these parts have gone together and come apart, wearing away each time.

What solutions can anyone offer?

[PackardV8]

What's worked for me on female threaded fuel pumps is to use a NPT tap to open the threaded hole just a bit more so the fitting will clock correctly. Coat the tap with grease so it will retain the very few shavings. Tap, try the fitting. Turn the tap a bit more, try the fitting.

jack vines

[Ron Dame]

Oh, I like that idea!

[Mike Van Veghten]

DON'T use Teflon tape.
Even plumbers, that it was made for...don't use it in most cases (as told to me by a...plumber !)..!
If you want to use teflon, use Teflon "paste".
If you feel the need to use a sealer, just use a little, non-hardening gasket sealer.
Me, for the last 50 or so years, I've just used...engine oil..!

I can't count anymore how many people that I've helped with oil or fuel pressure problems...and ended up finding Teflon tape in the system..!

Mike

[bensherb]

I can't count anymore how many people that I've helped with oil or fuel pressure problems...and ended up finding Teflon tape in the system..!
Mike

It was clearly not installed properly. Very common.

[64studeavanti]

I have used hylomar successfully in these situations.

[Ron Dame]

I finally cried Uncle, and pulled the fuel pump off. Strange how awkward the forward bolt is to access.

What I found is that the fitting is bottoming out before the NPT threads seal, so I went to my junk bin and pulled several other fittings regardless of the outlet end, and all did the same. So the pump body threads are worn too much. This is an original Carter that has been rebuilt with ethanol resistant parts, so I hate to trash it. We've already discussed the pitfalls of teflon tape, I'm not sure teflon pipe dope is any better in this instance, and not only are there no Helicoil pipe thread inserts (AFAIK) I doubt that will seal.
I'm leaning towards JB Welding the fitting in place. Pro's? Cons? better ideas? Would Hylomar handle a loose connection well without it moving around?

[sweetolbob]

I finally cried Uncle, and pulled the fuel pump off. Strange how awkward the forward bolt is to access.

What I found is that the fitting is bottoming out before the NPT threads seal, so I went to my junk bin and pulled several other fittings regardless of the outlet end, and all did the same. So the pump body threads are worn too much. This is an original Carter that has been rebuilt with ethanol resistant parts, so I hate to trash it. We've already discussed the pitfalls of teflon tape, I'm not sure teflon pipe dope is any better in this instance, and not only are there no Helicoil pipe thread inserts (AFAIK) I doubt that will seal.
I'm leaning towards JB Welding the fitting in place. Pro's? Cons? better ideas? Would Hylomar handle a loose connection well without it moving around?

Because it's a tapered thread, how about trimming off a thread or two from the fitting to get to a wider area of threads. If there's not enough length, try finding a new brass one at a local store that might have more threads.

I like Permatex better than Teflon for these issues also.

Bob

[64studeavanti]

Could you retap for a larger fitting? Maybe something metric.

[1inxs]

Permatex Aviation has been successful for sealing my fuel leaks. Even in cases where I was unable to get one last quarter turn to get a snug fit. Never a leak!

[Jeffry Cassel]

Ditto on aviation Permatex. Don't overdo any sealant. Don't think Teflon tape is the problem--the problem is how it is applied. I should be applied over the threaded area only . Great idea with the tap!

[Ron Dame]

Well, I lost the thread where I used a supposed gas and alcohol proof sealant. And it worked for a couple of years, but smelling gas again, I find that same fitting is leaking and loose. It's time to stop messing around.
I have an electric pump on a momentary switch to help start it when it's been sitting a week or so, and I guess I'll just set it up to run the truck all of the time.
But now I can't find the thread on how to wire the pump safely. I sure wish out search function worked better.

[altair]

When dealing with these small pipe/tube fittings it is important to know what thread it is, there are machine threads, tapered pipe and straight pipe, if they are mixed it will never work. Some fittings seal by bottoming in to a design male female, other taper pipe threads seal taper for taper. If you insert a taper thread into a straight thread it will not seal, although both will have the same TPI. I have a jar of fittings and it is most difficult to acquire a perfect match, you really have to what you have.