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Fuel tank

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  • Fuel tank

    Great site! I just signed up and it's proving to be very helpfull. I just bought a 77' 17' mako. The first project was to remove the console to refinish it. Once removed I took off the inspection cover above the tank to check it out. The foam is wet with water and there is gas fumes, I belive the water was leaking in around the larger hatch as it was not well sealed. The fuel leak is still a mystery, I am preparing to check hoses and pressure check. I removed some foam and found that the tank is coated on the outside with a black coating.

    My question is, does anyone know if the origional tanks were bare aluminum or did they have a coating around them? I am trying to determine if this tank had already been replaced.
    Sharkbait[br]1977 17\' mako

  • #2
    Hi Signman,

    The 17s' had a bare tank in them. When I replaced my tank I coated it with zinc chromate and then coated it again with a flexable urathane. Most new tanks are made with a higher corrosion resistant aluminum. I would still go through the extra steps to protect it.


    • #3
      Sounds like your tank has Coal Tar Epoxy on it?

      I'd pull everything out and inspect it. Your halfway there now. The piece of mind will go a long way.


      • #4
        Thanks for the replys!

        Today after writing the first message I went back out and continued to excavate and investigate. First, I found an original label for the tank dated 1976, whatever the black stuff was it came off very easily probably because of the fuel leak. The vent hose was almost completly destroyed leaking fuel into the surrounding foam for many years. I removed the tank and although I have yet to dig out all the foam from the area the tank sat in what appears to be a tub of some kind isolated from the rest of the bilge possibly to contain a mishap like this. I think the previous owner is lucky to be alive, all the foam I have removed so far is wringing wet with gasoline, someone else on this site I think refered to this as a bomb waiting to go off.

        I have not pressure tested the tank yet so I'm not sure of it's condition. Has anyone looked into the permanent-mount polyethlene tanks instead of coal taring the aluminum ones? They are inexpensive and sure seem like a worry free installation.
        Sharkbait[br]1977 17\' mako


        • #5
          Coal tar came right out of the 60's and 70's. If you want to protect an Al tank nowadays use a 2 part epoxy paints - I think it's a 2 part epoxy cromate primer and a 2 part epoxy top coat that is made especially for Al that is exposed to salt. Should last almost indeffinately - but remember to follow the epoxy manufactures recommendations exactly. Most mandate that the entire tank is ruffed up (with a light sanding or glass beading to remove the outside oxidation layer) before applying any type of epoxy paints. Oh and the other thing is, don't fall down when you see the price of the paint - Just remember you get what you pay for and if you don't want to do this job again do it right the first time. And the other thing is, I would not go with any Poly type tank that is hidden and foamed in (like in a Mako). Stick with the tried and true - Aluminum - manufactured by a company that is uscg certified to build certified AL marine gase tanks.

          Hope this helps -

          1973 22 CC Milford, CT USA[br]