Aluminum Fuel Tank Leaking?
 

Recently I've noticed the smell of raw fuel in the cabin area of my 1986 Scarab 1. I removed the gas tank cover in the middle of the cabin and found old stiff fill/vent hoses, an ok shape fuel line, an older looking sending unit, and what looks like some raw fuel/water in the 2 bunks just forward of the gas tank. In the cuddy it stunk pretty bad of raw fuel since it's enclosed. Around all of the fittings, lines, sending unit I didn't really smell any gas. The moisture is at the bottom of the bunks and that's where the smell is the strongest.


I'm going to go ahead and replace all hoses, sending unit, anti siphon valve etc, clean up the fuel as best I can and see where I end up. I'm concerned that the tank is leaking at the bottom where I can't see. Any thoughts based on the pictures I've shared? Thanks in advance!!

https://i.imgur.com/571PaNv.jpg
https://i.imgur.com/ZqknfwP.jpg
https://i.imgur.com/Mrsmwdb.jpg
https://i.imgur.com/3VgLjh0.jpg​​​​​​​​​​​
https://i.imgur.com/k6LEZ3u.jpg

​​​​​​​​​​​​​Heath

You can always pressure test the tank...That said, I had a good fried have a boat blow up around him when the key was turned due to a tank leak. He, luckily is still with us. You do not want to go boom. Going boom is not good unless you have a desire to look like a freshly roasted marshmallow

Your tank is leaking and it needs to be replaced. Probably has small pin hoes in the bottom which water over many years eroded thru

Good idea, I think i will go ahead and replace everything with new and then pressure test the tank. I'm glad your friend is ok, that scenario is my number one concern.

Ouch.. The certainty in which you say that has me concerned. Doesn't look like a fun job if that's the case.

Pulled mine out years ago and it isn't fun. Water is what rots out aluminum over time. It sits inside and slowly eats thru, or from the outside with same purpose. Keep the water away and aluminum last for ever

Makes sense. I think pressure testing before I pull anything apart makes sense. Really will suck if it's the fuel tank, I just had paint work and new interior done waiting to be put back in. Any ideas on cost to have this done? Bunk wall directly in front of tank would need to be removed for tank to slide forward enough to get it out. I know the foam on the sides and underneath holding it down are a pain, wonder what cost I'm looking at?

when my tanks were leaking we put a rubber tip blow gun in the vent and pressurized the tank.gas bubbled up out of the foam around the tank. as others said it was corroded at the bottom

well I can tell you this, back in the mid-late 90's a friend of mine had a shop that did a lot of warranty work for wellcraft. one of the main things they did was replace fuel tanks in their boats. unfortunately while cutting the floor out of one to remove the leaking tank he hit something that sparked and it went boom. he died a few days later. if you have ANY concerns that it is the tank do not think you can deal with it later and be very careful when working on it.

That is unbelievably tragic, I'm sorry about your friend and point well taken. There is no power to the boat (battery is out), and I will not be running any power tools around the area until I flush all of the fuel out. My plan currently is to pressure test the tank, and if a leak is confirmed (I'm assuming it will be) then I will attempt to remove it on my own. Before doing so I will obviously siphon all of the fuel, then I'm thinking of filling the tank slap full with water, siphoning out, then starting to cut the foam out for tank removal.

Two ways to remove tank that I can see. The tank is partially tucked under the rear seat probably 12 inches or so. I either have to cut the bunk wall forward the tank, cut the rear seat bolster, or cut the tank in half to remove..

I'm leaning towards cutting the tank in half to get it out and replacing with a moeler plastic prefab tank that's smaller than the existing 43 gallon tank that's in it to avoid having to cut any structure... So long as I can figure a way to do this safely and mount the new tank solidly in place.