Tank Fuel Pickup Sheared Off

[SouthCarolina1]

Today I was helping my buddy replace his fuel supply line on his center console boat. When he went to cut the fuel line off the barb fitting coming from the fuel pick up tube the top sheared right off. The tank has a fitting that the fuel pickup tube was threaded in. We tried loosening the fitting going into the tank but the top hex sheared off! The fitting in the tank bottom half is still attached but the top had the threads for the fuel pickup tube. I am considering trying tab what is left of the fitting in the tank to 3/8” npt and then installing a 3/8” to 1/4 adapter and then installing a new pick up tube. Or tap whats left, plug it, and replace the fuel sending unit with a built in pickup. Hindsight is 20-20 so don’t blast me for what we should have done. Any other options or different way of installing a new pickup in a plastic tank? Any advice for moving forward is welcomed. Also this area is only accessible through a 12”x12” opening in the floor under the console. To remove the tank we would have to take the top half of the boat apart. Drop links for recommended parts.

 

[alldodge]

plastic tank

Agree, I would try the tapping for NPT. Might think about remove some more of the floor to gain better access. Would be great if another layer of plastic could be glued on top the area to give more surface. There are some adhesives which should work, but most are for patching. Can be found searching for plastic gas tank repair

 

[roscoe]

Which part will fail next?

Time to replace it all by the looks of it.

 

[tpenfield]

I'm thinking the tank needs a new one or be taken out for a refurbishment.

 

[MTboatguy]

I would bet that tank is going to be prone to a failure in the near future, if it is brittle at the fittings, you can assume all of the plastic is brittle and could crack.

That said, you can buy a plastic welding kit at HF and actually weld a new flanged barb fitting on the tank, we used to fix water tanks that way for RV's when I helped at my buddies RV business. It is not a real difficult process, clean up the area real good and the "welder" is a directed hot air gun and you get plastic welding rod of various sizes.

 

[alldodge]

MT a hot air gun (glows heat hot inside) and use it around gas?

 

[MTboatguy]

MT a hot air gun (glows heat hot inside) and use it around gas?

You have to drain the tank and normally this welder is not hot enough to ignite the fumes. It is not the big hot are guns that we use for shrink wrap and such, they are small discharge and are designed to melt the little plastic rod that fuses the two parts back together.

Do not try on a tank that has fuel in it and let the tank air out after you have drained it.

It is done in the RV business all the time a lot of RV's now have plastic fuel tanks in them.

That said, my first suggestion is get a new tank, that one is brittle and getting close to end of life.

Most tanks are thicker in the area that has the fitting so once it starts breaking there, the rest of the tank is prone to breaking from vibration.

 

[w2much]

Your issue is what I avoided last year. I wanted to work on my old tank sending g unit. While there I thought to pull the pick up tube for cleaning a​​​​​nd inspection. Had I gone ahead I would be where you are now. Of course your friend needs a new tank, so do I but it is not in the cards. Welding polypropylene is extremely difficult if not chemically incompatible if you have not done itbefore. Let us know what you come up with. Tapping out the fitting seems like your best solution. 1/4" may not allow enough fuel flow.

 

[Chris1956]

I doubt taping will work, as a lot of plastic tanks have metal threads molded into them, which is the only strong way to attach fittings..

A brass garboard drain fitting is pretty close to a fuel pickup fitting. It has NPT which can be adapted with a flush bushing to mate with a fuel pickup. You would need to install bolts (or nuts) inside the tank to snug it down over a gasket and some suitable sealer. Can you reach into the tank via the fuel sender hole?

If not the tank is pretty close to end-of-life, IMO.

 

[Willyclay]

A brass garboard drain fitting is pretty close to a fuel pickup fitting. It has NPT which can be adapted with a flush bushing to mate with a fuel pickup. You would need to install bolts (or nuts) inside the tank to snug it down over a gasket and some suitable sealer. Can you reach into the tank via the fuel sender hole?

Great idea! I took a plastic tank to the dump yesterday that may have been salvageable using your suggestion.

 

[SouthCarolina1]

I just realized I never updated this thread! I ended up using some 3/8” aluminum to make a new pickup mount. Tapped the center hole to 3/8” and drilled holes for the mounting screws. I cut a gasket out and heavily applied permatex fuel gasket sealent to both sides of the gasket I made. I used SS screws made fir threading into plastic. I turned out great. After the permatex had cured I plugged both the vent and fill line. With a full tank of new gas I pushed down on the tank and I didn’t observe any leakage. Redneck pressure test SAT.

 

[Willyclay]

Attaboy!