Pressurized dual line gas tank

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  • Blake Monroe

    US Member - 2 Years
    Replies: 26
    Topics: 8
    #252642

    I could use some advice as a newbie to this hobby. Are all dual line remote gas tanks pressurized? I thought I saw a post where I saw a tank that had dual line but somebody replied it is not pressurized. What years were the Dual line tanks used primarily?


    labrador-guy

    US Member - 2 Years
    Replies: 661
    Topics: 50
    #252644

    Blake I guess I can take a stab at your question. Yes they do have pressure from the motor to move gas to the carb. The pressure two line tanks on OMC motors showed up on the 1949 QD 10 hp Johnson. Evinrude picked them in 1950 on their 14hp fastwin. They stayed around until 1958. The 58 lark and the Javelin had single line systems. I am sure I will be corrected if that is not so! OMC experimented with the single line tank on some gale models somewhere around 55 or56. You can use a pressure tank on a fuel pump motor if you make an adapter. Fisherman 6 has an adapter on some of his videos if you look for them on utube. Mercury had a pressure system also but I am not so sure of the years.

    40 below Joe….who wants to play cards!

    • This reply was modified 4 months, 1 week ago by labrador-guy.

    westwind

    Canada Member - 2 Years
    Replies: 371
    Topics: 10
    #252646

    This style tank is often confused as a Pressure Tank, but it isn’t. Key difference is the filler cap which is just a quarter turn gas cap, rather than a threaded on cap that seals for pressure.

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    Blake Monroe

    US Member - 2 Years
    Replies: 26
    Topics: 8
    #252739

    The picture of that tank helps. That’s the one I have and it looks like a dual line tank with dual line fittings. Is the second hose just for an air vent? I’m curious what years and models those tanks were typically used on and what the difference between that set up in a single line setup is for that tank in particular.


    Tom

    US Member - 2 Years
    Replies: 539
    Topics: 48
    #252743

    The two hose tank uses air pressure from the motor in one line to pressurize the tank. That pushes fuel in the other line up to the motor. Motors which use the twin hose tank usually have a tap at the bottom of the intake manifold where the air pressure is generated using crankcase pressure and a flapper type check valve.

    T

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    crosbyman

    Canada Member - 2 Years
    Replies: 2717
    Topics: 269
    #252744

    reset….. what motor do you have or trying to buy ?? . the motor defines the tank you need. that is the starting point.

    single line hose and tanks are for motors able to pump (suck) the fuel out of the tank…generally speaking .. late 50s onward engines come with pumps & a vent is used to let air IN to replace the consumed fuel

    Dual ine hoses and tanks are for engines with an internally configured air pump utilizing crankcase pressure to push compressed air into the sealed tank to push the fuel to the engine. These tanks come with a small top mounted hand pump (button) to manual pump a small quantity of fuel to start the engine and begin the process of pressure build up in the tank needed to ” push” fuel back to the engine. The tank is seal to prevent pressure loss otherwise the fuel would not be pushed back up the hose to the motor otherwise manual pumping would be needed to keep the motor going !

    as a member of AOMCI you have access to the Johnson Service manual (bible) aka RED BOOK where all this information is explained.

    the book is free for download at

    MEMBERS ONLY tab….INNER SNACTUM…tab…go down to LIBRARY….go down to GARRY SPENCER’S DROP BOX…. then all the way down to JOHNSON SERVICE MANUAL

    download it to a PDF file on your PC

    Joining AOMCI has priviledges 🙂

    • This reply was modified 4 months, 1 week ago by crosbyman.
    • This reply was modified 4 months, 1 week ago by crosbyman.
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    Blake Monroe

    US Member - 2 Years
    Replies: 26
    Topics: 8
    #252759

    All of your replies have been so helpful. The Motor I’m trying to specifically find the right tank for is a 1955 Johnson five and a half horsepower cd-12. I think it takes a pressurized gas tank. I’m attached pictures of two tanks I have one dual line pressurized in one which I thought was dual line but I guess it’s non-pressurized. The non-pressurized tank would go to what kind of motors such as years of make and type of model?. Also have a 1953 Johnson Q D14 10 horsepower , but it looks like it’s been retrofitted with an external fuel pump already. Would the non-pressurized tank work on that? All of my other Motors are internal gas tanks.


    seakaye12

    US Member - 2 Years
    Replies: 797
    Topics: 101
    #252764

    Your non-pressurized tank; while older in appearance….is a standard OMC fuel tank and is usable on any motor with a fuel pump from the 60’s on up. Same fitting that they used up to present times.

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    DAN UMBARGER

    US Member - 2 Years
    Replies: 169
    Topics: 19
    #252765

    Yes, The non pressurized tank would be used on your 10 hp which appears to have a fuel pump mounted on it and the pressurized tank would go to the 5 1/2 hp. Like Seakaye12 said the non pressure tanks use the newer style 2 prong fitting from the 60’s to the present.


    crosbyman

    Canada Member - 2 Years
    Replies: 2717
    Topics: 269
    #252766

    “The Motor I’m trying to specifically find the right tank for is a 1955 Johnson five and a half horsepower cd-12. I think it takes a pressurized gas tank.”

    Yes it does simply by looking at the side connector which has a fuel and air connection

    “I’m attached pictures of two tanks I have one dual line pressurized in one which I thought was dual line but I guess it’s non-pressurized” . ……………. A dual line tank is a PRESSURIZED tank

    “The non-pressurized tank would go to what kind of motors such as years of make and type of model?.”

    …. NON PRESSURIZED single line (hose) tanks work on all NON _PRESSURIZED applications generaly post 1959 or some late 50’S models as listed above in post #252644

    “Also have a 1953 Johnson Q D14 10 horsepower , but it looks like it’s been retrofitted with an external fuel pump already.” ….. ODD these mods simply invole the mounting of a modern pump UNDER the cowl.

    “Would the non-pressurized tank work on that?” if the QD is modified for a common modern pump then the tank (single hose) will work

    here is how it is done… see utube. the mod requires the installation of a single line side connector … but the older 2 line connector could be use if you use just the fuel half of the hose of it leaving the AIR side in place and plugged at he tank end ….. just for looks on a vintage motor.

    Joining AOMCI has priviledges 🙂

    • This reply was modified 4 months, 1 week ago by crosbyman.

    kirkp

    US Member - 1 Year
    Replies: 238
    Topics: 16
    #252984

    Blake, a thought about your question on a pressure tank that really wasn’t. There are some members that have converted their motors to use a fuel pump but they have used a dual tube fuel line for originality. Possible that is what you are thinking of?

    Kirk

    1 user thanked author for this post.

    crosbyman

    Canada Member - 2 Years
    Replies: 2717
    Topics: 269
    #252986

    and if you plan on using a dual line  hose set up with  a pump eqpted engine  may as well try to modify the purge  valve and route  polluting fuel oil juices back into the tank which will need to used with the cap loose .

    this will  prevent the dumping of  “purged” fuel & oil in the water 🙂

     

    see recent posts on the mod required to do this

    Joining AOMCI has priviledges 🙂

    1 user thanked author for this post.
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