Fuel tank inspection port

Smack

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My pressed-in rubber bung and fitting arrangement is leaking quite a bit of fuel (I'm guessing the hole drilled in the fiberglass is too large), so I am searching for a solution.
Regardless of the fitting I end up choosing, I have to break in to the fiberglass tank's interior.
Most likely I will 'glass-in' a metal (stainless) female fitting for the fuel exits.
Since I have to breach the tank, I'm thinking that an inspection port (in case I have to go in again) on the top (upper most) surface is an idea to explore.
I could design/build a stainless steel flange and cover, but I'm wondering if a screw-on plastic style, similar to what I am familiar with as a boat hull inspection port, would work. The plastic would have to withstand gasoline and I haven't researched the material commonly used yet.

Has anyone installed a 4-6" fuel tank port on a fiberglass tank?

Brian
 

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Here is a photo of the fuel tank fittings.
 

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Sv.grainne

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Are there 2 taps into one tank or one each into separate chambers?

The fitting I installed was a really tight fit into and existing hole. Did you have to drill these?

Bobby
 

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Two holes each tank.
Holes drilled and fittings installed by the factory. Leaked immediately upon receipt of fuel.
 

Sv.grainne

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When I was in the boat repair business I used to use frp threaded pipe which could be set into plastic tanks using epoxy resin. You could try these, https://www.frpsupply.com/frp-coupling/ . I always got the 4" long pipe, and cut out a section from each end that I could glue into the tanks. The 3/8" npt threads would work great for this. As far as an access port? I've seen them on water, waste and diesel tanks but not on a gas tank.
 

Sv.grainne

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Two holes each tank.
Holes drilled and fittings installed by the factory. Leaked immediately upon receipt of fuel.
Bummer, has the factory suggested a potential fix? My pickup port was factory drilled I installed the fitting but had to add my return port to the top of the tank.
 

Aviomania

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Hello Brian.

You were supplied with new rubber bushings. Theses need to be replaced ( or installed) when ready to add fuel. staying dry for a period of time makes the rubber hard and does not seal properly.

Once you add fuel you need to keep some fuel in the tank. If you let them get dry for some time they will leak again.

The pick ups are installed from the outside... no need to access the tank from the inside. Just install fresh bushings and all should be fine.

as an alternative (additional security) you can apply some silicon sealant on the seat of the bushing when you are inserting it. Rubber bushing goes in first and then the metal pickup.

repairing the hole (if necessary) can be done form the outside with epoxy but that will not be necessary. Even if the hole is a bit bigger we have metal inserts that are a bit larger and expand the ruber bushing more........

But as i said... the most common reason for the leak is that the bushings become dry and hard. Just replacing the ruber bushing with fresh ones will solve the issue.

Email me with the results and i can give you more details if needed.
 

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Replaced the 4 rubber bushings yesterday and put in about 1/2 gallon of fuel, no leaks from left-side tank.
The deeply recessed fuel cap makes it a bit challenging to add fuel without spilling; wish the fuel cap was more accessible.
Will put more fuel in this week to test right-side tank.
Inspection port and fitting replacement on-hold.
 

Smack

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Update, walked into the hangar mid-morning to find the smell of raw fuel.
I took a chance and let it sit overnight with some fuel in the right tank.
This morning, I find much of that fuel has found its way to the hangar floor.
Only the new front rubber bung appears to be leaking, but 50% is not quite good enough and these sat in fuel overnight, so I'm going to discount the 'dried out' theory.
Back to 'Plan A'.................
 

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Aviomania

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Brian, Please take out the leaking pickup and email me few pictures of the tank hole.... to make sure there is no other problem. Normaly the leak should be due to some dirt/ particle at the perimeter of the hole. On some occasions the toleranse of the bushings is litle off. You were provided with 8 new bushings rather than 4 that you need...... once i see the pictures and confirm that there is not any other damage on the tank hole i will send you couple of oversized pickup inserts so that you solve your problem. I will also resend some new rubber bushing in case the rubber of the bushings you have became hard ( its been some time you have them now)....

Please include your postal address in the email so i can send the pick ups to you.
 

Sv.grainne

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Replaced the 4 rubber bushings yesterday and put in about 1/2 gallon of fuel, no leaks from left-side tank.
The deeply recessed fuel cap makes it a bit challenging to add fuel without spilling; wish the fuel cap was more accessible.
Will put more fuel in this week to test right-side tank.
Inspection port and fitting replacement on-hold.
Brian:
The tank fill location on my Genesis is a bit awkward as well so I purchased a 14gal wheeled gas container that has a small battery powered pump. A minor mod to the nozzle end and it works great. I use a flashlight when topping off so I avoid any overfill.

Bobby
 
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