Fuel leak (with pic)

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  • capnward
    Afourian MVP
    • Aug 2012
    • 335

    #16
    Be attuned to the smell of gas, your nose is as good as any fume detector, use it often. You should not be able to smell gas, if you do there is liquid gasoline somewhere outside the air intake to the carb. Find the leak before using anything electrical. Sometimes there is a little gas in the bottom of the air intake to the carb, under the flame arrestor, but as long as it is not leaking out through the choke lever area and dripping into the bilge, you are probably ok. I am a great believer in using the hand bail on the mechanical pump and a fuel pressure gauge to see if there are leaks. Lots of ventilation is your friend. Even if there is a puddle of gas in the bilge, it may not explode if enough air is moving over it. It is the concentration of fumes with an ignition source that is dangerous. Air temperature is a big factor as well. Your reaction to the smell of gas should be alarm.
    I will never forget the day in the 1980's when I opened the companionway and was hit by an overpowering gas smell. I had been gone for a few days. I had let an acquaintance borrow my portable gas tank, and when he returned it, he put it on something that tipped it over when the wind came up, and 5 gallons drained out of the air vent into the bilge. There was maybe an inch of liquid gas when I lifted the cabin sole to inspect. I immediately shut off the shore power at the dock outlet. In hindsight I should have done that before opening the bilge, but I was lucky. The amazing thing to me was that sitting on the cabin sole, directly above the puddle of gas but separated by three inches of air and 1/4 inch of plywood, was an electric ceramic disc space heater with a fan, happily blowing warm gas fumes around inside the cabin, and through the heating elements. It had been going constantly the whole time of the gas spill, and had evidently kept the fumes from being too concentrated. It may even have reduced the concentration by combusting fumes in the heating elements without igniting them, if that is possible. If it had been set to turn off and on to keep the temperature at a certain level, it may have blown up the boat. But as it was winter, and I was living aboard, it had been set on high, and stayed on. Once the power was off I opened up the boat as much as possible and started to remove the gas from the bilge using cups, sponges and oil pads. It was a plywood boat with a dry bilge, and the smell lingered for many days, but eventually stopped.
    Ever since then I have been highly sensitive to the smell of gas. I would not be able to sleep, let alone run anything electrical, until I had found the source of the leak and fixed it. I always leave the engine compartment open so that the whole interior of the boat is the engine compartment, and air is flowing through it. Blowers are essential to ventilate the engine compartment, if it is enclosed. The blower hose should be led right up to the carburetor. But I don't use a blower unless I smell gas. I prefer to leave the engine completely exposed to all the air flowing through the cabin, and open up hatches fore and aft to maximize that flow when the boat is moving. I think it is important to keep fumes from concentrating in the first place. Plus, if fumes are contained in a closed engine compartment you can't smell them.

    Comment

    • Marty Levenson
      Senior Member
      • Nov 2004
      • 679

      #17
      narrow it down

      "Be attuned to the smell of gas, your nose is as good as any fume detector, use it often. You should not be able to smell gas, if you do there is liquid gasoline somewhere outside the air intake to the carb. Find the leak before using anything electrical. Sometimes there is a little gas in the bottom of the air intake to the carb, under the flame arrestor, but as long as it is not leaking out through the choke lever area and dripping into the bilge, you are probably ok."

      This fall I installed a switch to shut off the electric fuel pump, letting the carb run dry for shutting down. That way if I smell gas below I know it is not the carb. Also keeps the carb cleaner.
      Marty
      1967 Tartan 27
      Bowen Island, BC

      sigpic

      Comment

      • Mattlurzo
        Senior Member
        • Aug 2018
        • 22

        #18
        Originally posted by capnward View Post
        Be attuned to the smell of gas, your nose is as good as any fume detector, use it often. You should not be able to smell gas, if you do there is liquid gasoline somewhere outside the air intake to the carb. Find the leak before using anything electrical. Sometimes there is a little gas in the bottom of the air intake to the carb, under the flame arrestor, but as long as it is not leaking out through the choke lever area and dripping into the bilge, you are probably ok. I am a great believer in using the hand bail on the mechanical pump and a fuel pressure gauge to see if there are leaks. Lots of ventilation is your friend. Even if there is a puddle of gas in the bilge, it may not explode if enough air is moving over it. It is the concentration of fumes with an ignition source that is dangerous. Air temperature is a big factor as well. Your reaction to the smell of gas should be alarm.
        I will never forget the day in the 1980's when I opened the companionway and was hit by an overpowering gas smell. I had been gone for a few days. I had let an acquaintance borrow my portable gas tank, and when he returned it, he put it on something that tipped it over when the wind came up, and 5 gallons drained out of the air vent into the bilge. There was maybe an inch of liquid gas when I lifted the cabin sole to inspect. I immediately shut off the shore power at the dock outlet. In hindsight I should have done that before opening the bilge, but I was lucky. The amazing thing to me was that sitting on the cabin sole, directly above the puddle of gas but separated by three inches of air and 1/4 inch of plywood, was an electric ceramic disc space heater with a fan, happily blowing warm gas fumes around inside the cabin, and through the heating elements. It had been going constantly the whole time of the gas spill, and had evidently kept the fumes from being too concentrated. It may even have reduced the concentration by combusting fumes in the heating elements without igniting them, if that is possible. If it had been set to turn off and on to keep the temperature at a certain level, it may have blown up the boat. But as it was winter, and I was living aboard, it had been set on high, and stayed on. Once the power was off I opened up the boat as much as possible and started to remove the gas from the bilge using cups, sponges and oil pads. It was a plywood boat with a dry bilge, and the smell lingered for many days, but eventually stopped.
        Ever since then I have been highly sensitive to the smell of gas. I would not be able to sleep, let alone run anything electrical, until I had found the source of the leak and fixed it. I always leave the engine compartment open so that the whole interior of the boat is the engine compartment, and air is flowing through it. Blowers are essential to ventilate the engine compartment, if it is enclosed. The blower hose should be led right up to the carburetor. But I don't use a blower unless I smell gas. I prefer to leave the engine completely exposed to all the air flowing through the cabin, and open up hatches fore and aft to maximize that flow when the boat is moving. I think it is important to keep fumes from concentrating in the first place. Plus, if fumes are contained in a closed engine compartment you can't smell them.
        Thank you! I totally understand what you're saying and your story helped illustrate what could happen. I like the idea of opening everything up to dissipate things. Great insight.

        Comment

        • ndutton
          Afourian MVP
          • May 2009
          • 9601

          #19
          Unfortunately opening things up is not effective for dissipation because gasoline vapors are heavier than air. They will settle in the bilge and stay there. This is the reason we have powered ventilation that draws air from low in the boat and exhausts it overboard.
          Neil
          1977 Catalina 30
          San Pedro, California
          prior boats 1987 Westsail 32, 1970 Catalina 22
          Had my hands in a few others

          Comment

          • capnward
            Afourian MVP
            • Aug 2012
            • 335

            #20
            That's absolutely right. If you want to get the fumes out of the bilge, opening up the hatches and motoring around is not the remedy. However I believe ventilation of any kind around the engine helps prevent fumes accumulating in the bilge. If your engine is enclosed in a box, you can't smell fumes, and a blower needs to be running, with a special air inlet into the box from outside. In any case, use the nose.

            Comment

            • joe_db
              Afourian MVP
              • May 2009
              • 4474

              #21
              When my fuel fill elbow split and I put about 4 gallons of gas into the bilge, after cleaning up as best I could , I left the boat anchored into a stiff breeze with all hatches open including the cockpit lockers, the engine compartment open,, and the floorboards up. We did several cycles of fill the bilge with soap and water and then pump it out (by hand, not electric !!!)We went ashore for lunch and the boat was reasonably de-gassed when we got back. Automotive gas has a "stink" chemical that is very hard to get rid of I never realized this until I spilled avgas on my shoe and the smell was quickly gone. From what I read the stinky stuff was to keep kids from sniffing gasoline
              Joe Della Barba
              Coquina
              C&C 35 MK I
              Maryland USA

              Comment

              • Mattlurzo
                Senior Member
                • Aug 2018
                • 22

                #22
                Originally posted by ndutton View Post
                Unfortunately opening things up is not effective for dissipation because gasoline vapors are heavier than air. They will settle in the bilge and stay there. This is the reason we have powered ventilation that draws air from low in the boat and exhausts it overboard.
                That's right. it's probably why even after airing things out, the smell still lingers in the bilge. I'm hoping the "De-oil it" will neutralize the gas fumes as it works on any residue left in the bilge. $35 for the small bottle -- I'm hoping it does what it professes.

                Comment

                • ndutton
                  Afourian MVP
                  • May 2009
                  • 9601

                  #23
                  Forgive me for being blunt but are you running the bilge blower? This is exactly why you have one - - - or should. I read back through the thread and did not see any mention of it.
                  Neil
                  1977 Catalina 30
                  San Pedro, California
                  prior boats 1987 Westsail 32, 1970 Catalina 22
                  Had my hands in a few others

                  Comment

                  • edwardc
                    Afourian MVP
                    • Aug 2009
                    • 2491

                    #24
                    Originally posted by Mattlurzo View Post
                    That's right. it's probably why even after airing things out, the smell still lingers in the bilge. ...
                    In my experience, spilled gas smell does NOT linger. Its one of the things I like about gas over diesel. Gas is so volatile that it evaporates and is gone. On the other hand, when you spill diesel on something, the oily residue and smell seem to last forever!

                    If you have a continuing gas smell after airing out (with a bilge blower), then I believe you have a leak.
                    @(^.^)@ Ed
                    1977 Pearson P-323 "Dolce Vita"
                    with rebuilt Atomic-4

                    sigpic

                    Comment

                    • JOHN COOKSON
                      Afourian MVP, Professor Emeritus
                      • Nov 2008
                      • 3500

                      #25
                      The Nose Knows

                      Originally posted by edwardc View Post
                      In my experience, spilled gas smell does NOT linger. Its one of the things I like about gas over diesel. Gas is so volatile that it evaporates and is gone. On the other hand, when you spill diesel on something, the oily residue and smell seem to last forever!

                      If you have a continuing gas smell after airing out (with a bilge blower), then I believe you have a leak.
                      +1 on this. If you have the fuel tank repaired so it doesn't leak and you still smell gasoline you have another leak somewhere.

                      TRUE GRIT

                      Comment

                      • Mattlurzo
                        Senior Member
                        • Aug 2018
                        • 22

                        #26
                        Originally posted by ndutton View Post
                        Forgive me for being blunt but are you running the bilge blower? This is exactly why you have one - - - or should. I read back through the thread and did not see any mention of it.
                        Yup. Ran the blower for half an hour last time I was there. I will check to see that it is working properly this weekend. Sounds good, but it may be clogged or something.

                        Comment

                        • Mattlurzo
                          Senior Member
                          • Aug 2018
                          • 22

                          #27
                          Originally posted by edwardc View Post
                          In my experience, spilled gas smell does NOT linger. Its one of the things I like about gas over diesel. Gas is so volatile that it evaporates and is gone. On the other hand, when you spill diesel on something, the oily residue and smell seem to last forever!

                          If you have a continuing gas smell after airing out (with a bilge blower), then I believe you have a leak.
                          Makes sense.

                          I know where the original leak was for sure. It's been fixed. It would be a terrible, but not impossible coincidence if a fuel tank or other leak occurred at the same time. I hope that's not the case. If I get all the water out, run the blower (after I make sure it's working properly) and the smell doesn't dissipate, I will investigate for another leak.

                          This has been great information. It really helps to get a full picture of what's been happening.

                          Comment

                          • JOHN COOKSON
                            Afourian MVP, Professor Emeritus
                            • Nov 2008
                            • 3500

                            #28
                            Sometimes the tubing comes loose at the outlet vent and falls off. Depending on the design of the boat this can be tough to see and repair.

                            TRUE GRIT

                            Comment

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