Stripped out Fuel Pickup Tube bung bushing in poly tank

[super_dork]

I am doing some tuning on my boat and decided to drain the fuel tank and check the pickup tube and fuel sending unit. This is a 1993 Stratos with a 28 gallon Inca Cross Poly tank. The sending unit has an original cork float on it but still works. The pickup tube seems original as well. Somehow, when I was removing or reinstalling, the threads on the bung bushing for the pickup tube and the tube elbow fitting got got stripped/rounded over for the first several thread rotations. My first thought would be to just replace both, however the bushing in the tank appears to have been installed from the inside of the tank with a nut on the top holding it tight. I'm afraid that if I attempt to remove this, I will lose it in the tank or won't be able to find a replacement or install it without great difficulty. So that leads me to thinking I should attempt to re-thread the tank bushing with a tap. It seems to be about 5/8" but I need to get a caliper to check for sure. I know that will end up dropping metal shavings into the tank, but I don't think I have much choice. I need to get a tap and die for this size - the set I have didn't go up that size.

Another option would possibly be to drill a new whole in the tank and seal the existing hole up.

This video has a very similar pickup tube and bushing as what I have. However, my other tank fittings/holes are at least 24" away from the pickup tube hole.


I could be completely off base and maybe this fitting just slides right in, I just don't know.


Anyway, I'm kinda stuck. Would love some input. Thanks!

[Rich1]

Go to the auto parts store or good hardware store, buy a heli-coil of the proper size. Follow instructions on heli coil, boat fixed

[wmitch2]

I would re-tap it. You can try magnetizing the tap and make a turn then removing it and cleaning any shavings off then go further on each attempt. Also, if you have limited access as in the video, use a “Crows Foot” wrench to tighten it back in.

[super_dork]

Go to the auto parts store or good hardware store, buy a heli-coil of the proper size. Follow instructions on heli coil, boat fixed

That's a good one to remember. Didn't know such a thing existed. In this case, it appears that the threads got folded over so they were closing in the opening rather than just missing threads and making a larger opening. I ended up finding a tap that got it working.

[super_dork]

I would re-tap it. You can try magnetizing the tap and make a turn then removing it and cleaning any shavings off then go further on each attempt. Also, if you have limited access as in the video, use a “Crows Foot” wrench to tighten it back in.

I went to the local boat shop and they had a new pickup tube assembly and agreed on attempting to re-tap. The local Ace hardware had a tap that worked. The issue I ran into is that the insert measures 5/8" but most places only went up to 1/2" taps. Even then, depending on the type of fitting, it would measure differently. If I threaded into a galvanized 3/8" pipe it fit. If I threaded into a 1/2" compression fitting, it fit. Ultimately, I used a 5/8" 18 NF tap. https://www.amazon.com/IRWIN-1554ZR-.../dp/B0195UVMCK. Not sure if it was the right tap since it was still tough to get the new fitting in. I used a brass fitting of the same size along with some oil and worked it in several times back and forth before fitting the very delicate aluminum replacement fitting. The oil helped trap much of the shavings.

Thanks for the response!

[JCV73]

I'm in the process of having two aluminum tanks built to replace my two poly tanks. When I replaced the sending unit, the riv-nut was stripped out on the Inca tank making it unusable. I had to cut the screw out so I was worried about metal shavings. I really did not want to spend the money buy I will feel better about my choice in the long run.

[bhjr.]

I wouldn't think that the threads would be any "straight" thread, but more than likely NPT threads, which are tapered.

[super_dork]

I wouldn't think that the threads would be any "straight" thread, but more than likely NPT threads, which are tapered.

I believe you are correct.

[alli ss]

I bet its 1/4-npt. Take your fitting to the store and hold it up to the tap and youll see. If you fill the flutes with grease it will catch the shavings- clean often. Get an industrial maintenance guy to help. Youd be surprised at how many tricks he will have up his sleeve