Fuel tank sending units

Discussion in 'Projects & Proposals' started by cassanova, Jul 23, 2007.

  1. cassanova
    Joined: Jul 2007
    Posts: 3
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    Location: Tennessee

    cassanova New Member

    Hello. I have been looking at the moeller gas tanks with an electric sending unit and my question is. Can I or would it be possible to replace my existing 12 gal. gas tank with one of these. I have a 55 evinrude outboard if that helps. I just get tired of having to monitor the gas level through the small window that is on the current tank. I guess most of all, would this be practical? Thanks in advance.
  2. stonebreaker
    Joined: May 2006
    Posts: 438
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    Location: Shiloh, IL

    stonebreaker Senior Member

    Anything's possible with enough motivation. :D

    Is your tank permanently attached to the boat? Doesn't sound like it, but just thought I'd ask.

    Assuming you can get your tank out and the new tank in without too much trouble, all you'd need to do is mount a compatible gas gauge and run the necessary wires (usually two or three) back to the tank, and get power for the gauge from your fuse panel. Just ask the seller what type of sending unit it has - GM, Ford, etc. and then buy a compatible gauge. The gauge should have a wiring diagram with it, and the tank should have a wiring diagram with it to show you how to connect it up.

    Just make sure you use different colored wiring for each lead. Saves time and frustration in the long run.
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    If you are attempting to convert an above deck tank to a remote gauge, it's real easy. A company called Tempo makes tanks, gauges and sending units (among other things) and their product number 420110 is a remote sending unit, designed to fit in a direct read gauge hole. It has the dinky little direct read gauge built in, but also has the sending unit. You'll need to install a gauge (on your instrument panel) and wire it up, which is also very easy. Gauges are standardized (35 to 240 ohms, they work by measuring percentage of ground, so there's no possibility of a spark).

    If you intend to use a below decks tank, maybe mounted above deck, where the old, portable one lives, then venting, ground and fill issues need to be addressed as well as the sending unit/gauge installation. A below deck tank will have a small diameter fitting (vent) which needs a hose attached and routed up and preferably through the hull's topsides, with free access to open air. This is because gas vapors are heavier then air and will collect in the lowest points of the hull, unless properly vented. Of course, this type of tank doesn't have a screw on filler cap, it has a bigger fitting, which receives a hose. The hose is routed to a handy spot and attached to a filler neck, which is what the cap (deck plate) screws into.

    West Marine also sells these pieces. Their numbers are 100893 (TRM-2 remote sending unit), 105140 (gauge) and the instructions with the gauge or sending unit are real easy to wire up.

    It also may be possible to install a universal sending unit in the top of your portable tank. These too have standardized bolt patterns and cutout holes. Getting a purchase on a plastic tank may prove difficult (mounting bolts/screws), but think it through and you'll get 'er done. An automotive sending unit is not wise, nor will like the marine inviroment. They also are not standardized in resistance (ohms), mounting and construction materals.
  4. Frosty

    Frosty Previous Member

    There is not standard gauges. European are the opposite to American, Ohms resistance varies tremendously. All you need is a gauge and a compatable sender. As long as they are matched you are laughing.

    feed is from Ign to gauge ,--from gauge to sender,--from sender to ground/battery neg. Usually one wire so the tank will be grounded/neg.

    As Par says the biggest problem is matching and fitting the sender to the tank.

    Usually Marine senders come totally adjustable to the tank depth.

  5. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Tempo, Morse, Todd, and Teleflex are the major players in the industry and all have adopted the same 5 hole plate attachment, same diameter mounting hole, identical wiring and same resistance range (35 - 240). I'm sorry the EU hasn't adopted similar standards, but the market is driven by the biggest consumer, unfortunately. This may be China in a decade or so.

    Frosty is correct in that you should insure the ohms match both the gauge and sender, but in the Volunteer state, he'll likely drop by the local marina, BoatUS or West Marine and pick up one of the standardized units.
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