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  • Fuel tank

    My first posting, looks like a great site!!

    I have a 1981 25' center console. The fuel tank is original. She has a spin-on recor fuel filter/water seperator installed. About every 25-30 hours the primer bulb begins to collapse and it's time to change the filter. Does my MAKO have a belly tank?? Could I use a 12 volt fuel pump, open the tank gauge plate, and suckout the bottom of the tank. Perhaps getting much of the water out?

    I do not smell any fumes, I hope the tank doesn't need replacement. Any and all ideas are greatly appreciated!!


  • #2
    RingLeader would know more about this, but I definitely think you have something impeding your fuel supply line; either at the Raycore filter or between it and the tank.

    I know that my Mercruiser has had the same filter for more than 2 years (yes, I need to change it) without getting a vaccuum lock like that. I don't think the filter is to blame if it's fairly recent.

    More importantly, has the boat sat up and just collected dust, mold, etc. for an extended time period? I would definitely find a way to send something (that would pick up debris) down the line into the tank to make sure it's clear.

    Anyone else care to comment?


    18ft MonArk tri-hull: 140HP Mercruiser Alpha One

    (I know it's not a Mako, but hey, its mine!)

    Time's fun when you're having flies!
    18ft MonArk tri-hull: 140HP Mercruiser Alpha One - still in be continued[br](I know it\'s not a Mako, but hey, its mine!)[br] Time\'s fun when you\'re having flies![br]president/hostmaster:[br]P.Ring Technologies[br]Cornerstone IT, LLC[br]LOUISIANA WEB HOST, LLC.[br]CompTIA Certified Professional A+/Network+ // Microsoft Registered Partner


    • #3
      Your Mako does have a belly tank. 151 gallons in size. The tank sits in a coffin of sort beneath the big hatch in the center of the floor (usually beneath the console area). It is held in this coffin by foam and when the seal around the deck plate breaks down, the foam saturates and speeds the corrosion process of the aluminum fuel tank.

      Some how or another water/debris is getting into the fuel tank. Maybe through the vent or fill hoses. Or maybe even a hole in the actual fuel tank where the water is getting into the tank. Check the vent line where it exits the boat and the fill line and fill fitting at the gunwale. Those are the 2 easiest places to start.

      If nothing presents there, then I would run as much gas through the motor until you are pretty close to empty. Then siphon the remaining gas out of the tank. I just don't like electricity around gas, so heres what I did. With the boat on the trailer, I used unhooked from the filter, the fuel line that comes from the tank to the filer. Then I put a primer bulb on that end that used to attach to the IN side of the filer and hooked a new section of fuel line to the other side of the bulb. Then I ran the new section of fuel line out of the bilge drain hole. I set it into gas cans to collect the fuel and pulled a prime on the line and gravity did the rest.

      Once all that gas is out you'll have to remove the console and tank deck plate and pull the tank up. I have a good set of instructions for doing this if you have to do so. Inspect it and have it pressure tested. If its still good then have it coated with coal tar epoxy and replace it back inthe boat with new foam.

      I'd make sure all the other possibilities are exhaused first.

      Slidell, LA 1993 Mako 261B - Temperance


      • #4
        Capt Fun-

        Considering that your 254 is a 1982 model, you should really think about replacing the tank. As Eddie mentioned, seawater and rainwater have a tendency to get soaked up in the foam surrounding the tank and over time will cause it to corrode.

        My buddy has the same exact boat as you and getting the tank out will be slightly difficult because there is not much room to work with between the tank and the liner.

        Regardless, dig out foam surrounding the tank (dont use any electric tools), pull out the tank and order a new one.

        When you replace the new tank, you may want to consider alternative ways of mounting the tank instead of using foam. Professional Boatbuilder magazine recently ran an article on this......I'll see if I can dig it up.

        Replacing the tank might cost you more than you wanted to send, but safety and piece of mind are well worth the extra $$$$.


        Ed Mancini

        1991 Mako 231

        Tournament Edition


        • #5
          A little trick that I came up with to get the foam free of the tank, is to use a Bow Saw Blade. The type you would trim tree limbs with. With just the blade removed from the saw frame. Wrap one end with cardboard and duct tape. That's to protect your hand. This blade has VERY agressive teeth and has enough reach to go all the way to the bottom of the hull. It makes quick work of getting the foam freed from the side of the tank and stringers.


          • #6
            If you have a problem with mud daubers (black wasps that make mud egg sacks/nests), its a given that they'll make nests in your vent lines if the boat sits at all for more than a month (unless you plug them). This debris can collect in the tank over time.

            Eddie, does this tank have an in-tank strainer screen?

            If it does, it could easily clog with the dirt, varnish (old gas/oil deposits), etc over many years time. (I know outboards and 4 stroke motors are way different beasts, but fuel problems are fuel problems.)

            18ft MonArk tri-hull: 140HP Mercruiser Alpha One

            (I know it's not a Mako, but hey, its mine!)

            Time's fun when you're having flies!
            18ft MonArk tri-hull: 140HP Mercruiser Alpha One - still in be continued[br](I know it\'s not a Mako, but hey, its mine!)[br] Time\'s fun when you\'re having flies![br]president/hostmaster:[br]P.Ring Technologies[br]Cornerstone IT, LLC[br]LOUISIANA WEB HOST, LLC.[br]CompTIA Certified Professional A+/Network+ // Microsoft Registered Partner


            • #7
              Here is a quick link that tells you one way of installing a fuel tank.

              Like the guys said foam can be a problem so I'd Stay away from it in if you can. If you do decide to foam it back in place then make sure there is a way for water to escape. Ring- I hope it was OK to post the link []

              Oakley, California


              • #8
                Absolutely! I sent out an e-mail saying that I'm not opposed to anything being posted here that is for the benefit of everyone here. I don't mind links to any other forum on the web. I go to 6 or 7 different forums daily and look for interesting reading. So if anyone finds interesting stuff elsewhere, link us to it!

                I am opposed to business promotion and advertising without my permission.

                Slidell, LA 1993 Mako 261B - Temperance


                • #9
                  Just a suggestion before you rip out the tank. We just did this on a 87 Wellcraft V-20...

                  We removed the sending unit through an access port. Using 2 sections of fuel line and a bulb as Ed suggested, we were able to stick one end of the hose through the sender opening to the very bottom of the tank. We pumped approx. 2 gallons of water/ coffee grounds out before we got good clean fuel. We then pumped out another 5 gallons to be safe.

                  Just my opinion but, I think a tank that old is going to collect condensate over the years along with water in gas that is purchased from time to time. Eventually the level of the water is going to get high enough to be picked up and sucked through the filters. That is what we found anyway. Once the bad dregs were removed and the filters replaced ..No more problems. We would have dumped the tank but 60 gallons is a lot of lawnmower gas.[V]

                  There was no problem with the motor prior to the day that it started missing and we found the water.

                  Be careful to isolate the wiring to the sending unit prior to removing it. I'm no electrician but it can't hurt.

                  Hope it helps

                  SMOKER 224
                  1983 Mako 224[br]Onancock, Va.


                  • #10
                    I realloy appreciate all the suggestions. I am going to the boat on the 15th of January. I am going to try the simplist first. I have found many problems only require a common sence solution and you have given me many.

                    Checking the vent and all fittings will be 1st. Next I'll try the suggestion about going through the sending-unit plate with a fuel line and draw off about 5 gallons and see what I get.

                    QUESTION Could I use a section of soft copper pipe(3') attached to the flexable fuel line to help make certain I'm at the bottom of the tank??

                    My last resort would be to pull the tank[V] Bill Pinkerton of Rivia Beach just installed a new T-Top and that would be a job in itself.

                    Again,many,many thanks. I'll be sure to post what I find.



                    • #11
                      Yes the copper or 3/8 steel line would work fine.

                      You can get the steel line at auto parts store.


                      • #12
                        Ring Leader,

                        I would be real interested in the info on pulling the original tank. I am currently digging out the foam from the top of my tank. Given the tight space between the deck work and the tank, how the heck do I break it free of the foam to remove it?

                        Thanks for your help!


                        1980 Mako 238 WA

                        "Mischief Mako"
                        Rob[br]1980 Mako 238 WA[br]\"Mischief Mako\"


                        • #13
                          I had the same problem removing my tank. The tank was sealed in on all sides by (waterlogged) foam and there's only an about an inch on all sides between the tank and the compartment walls it sits in. I started using a crowbar and a claw hammer to pull out the foam in chunks but finally needed to make a tool (long wooden stick with metal scraper on the end) to dig down around the base of the tank and pull out the remaining foam enough so that I could break the tank free and pull it out. You definitely want to siphon out all the gas first to keep it light. After removing I sanded and cleaned up the corrosion spots and coated the entire tank with Hi-Flex epoxy (similar to coal tar epoxy). I haven't re-installed the tanks yet but prefer not to foam them in again even with the epoxy coating. Just too hard to remove if they need to come out again for any reason.


                          • #14
                            When I did mine I had the sending unit out and installed a steel rod thru the hole. I then put my A-Frame over top of the boat and used a come-a-long to pull the tank. I do know that other people have used this method also.


                            • #15
                              I bought a grinding looking aparatus at home depot that was about 3/4 inch in diameter and came with a 12 inch rod, I chucked this in the drill and ground down both sides of the tank and then used a come along attached to a 4 x 4 across the gunwales and lifted it out. There are pics of me doing this if you look under Jon Bradfords 25 Mako. I broke a 4 x 4 originally then went back and used the apparatus I bought and cut off the foam on the side. By the way the 25 held roughly 122 gals in 2 separate tanks, I welded a new one out of aluminum myself and made if fit so tight that you do not need foam on the sides, it now hold 197 gals.