No announcement yet.

Fuel Sending Unit Repair

  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    I just used super glue


    • #17
      Originally posted by Worthing skier View Post
      Hi all

      My Fuel gauge reading was playing around a bit last seat season , normally reading low.
      With the track record of the sender units I have today taken it out with a view to find a magnet related fault , however the sender unit I have is a plastic tube and it does appear to have any retainer screws to enable me to get in side it .
      By tipping up and down I can see the float move around but it does get stuck , which I am sure the the route cause of the problem .
      There is a plastic plate on the bottom of the unit , which I would thin could be prised off and re glued .
      Has any one come across the type of sender unit and if so how did you get inside.



      1993 prostar 190 285 hp inamr.
      My '94 PS205 also has the plastic sending unit tube. After reading this thread I pulled the sending unit out and sure enough, the magnets were stuck to the back of the circuit board (I had to use a razor knife to cut the bottom plate off the tube). It looked like the magnets had been closer together, possibly one on the end and the other near the middle (based on where it looked like they had been glued), so this is how I reglued them. Now a few questions:

      - Should the magnets be at opposite ends of the float, with the poles repelling each other?

      - Are the magnets supposed to touch the circuit board as the float slides up and down? Mine appear to be about an 1/8" from the circuit board.

      - If I reassemble the unit and reconnect the wires, will the fuel gauge register full if I turn the sender upside down and let the float go to the top, or does the unit have to be submerged in fuel in order to work?


      "Measure your wealth not by the things you have, but by the things for which you would not take money."

      1994 MasterCraft ProStar 205, 275hp EFI -- Original Owner


      • #18
        Awesome write up, I pulled my sender this weekend and found 1 magnet completely dislodged. Works great now, hopefully it stays that way.


        • #19
          Great write up - thank you. I would only add that I only had one magnet on my float. I confirmed this by only finding one magnet when disassembling, as well as there was only one visible area on the float that anything was attached to. Not having another magnet handy, I tested successfully with one magnet (both ohm meter and fuel gauge). I do not want to confuse anyone off your instructions, just relaying my situation.

          Also, how did you manage to get the round/slotted nuts off to remove the circuit board? I ended up using vice grips to loosen although based on the amount of work I put into it --- I'm certain there must be the right/better tool given the slots on each side of the bolt.

          Thanks again - this is an awesome write-up!


          • #20
            Did you have to remoce the tank


            • #21
              Originally posted by jude09 View Post
              Did you have to remoce the tank
              You must at least disconnect the straps and pull it out to clear the sending unit. Really not that big of a job. Have to first remove the combing pads in the back corners. Then the carpeted back filler board. There are just clamps that lock onto the tank. Unscrew the clamps and the only thing left holding the tank in place is the filler hose.


              • #22
                Just did this repair on my '98 Prostar 190 a couple weeks ago after reading this thread. After disassembling the unit, I found only a single loose magnet inside the cylinder. I figured I had dropped the other one when taking it apart. Looked around nervously on the floor for a while, then inspected the float and saw only one end of the slot showed signs of old glue where only the single magnet would have been mounted. I carefully sanded the outside radius of the float to reduce its size and allow it to move freely up and down inside the cylinder, remounted the magnet with super glue, reassembled the unit, and it's been working fine for two weeks now.


                • #23
                  It was a heck of a lot easier just to buy a new one from Skidim.
                  Give me a break I'm just hangn' out!


                  • #24
                    But a heck of a lot cheaper and satisfying to do it yourself. Just completed this fix using this thread two weeks ago on my 96 prostar. Worked like a charm, and I borrowed the super glue so it didn't cost me a cent. Thanks very much!!!


                    • #25
                      "Easier to buy a new one"... Maybe... I'm not knocking Skidim here, I love the place and how helpful they are, but they haven't built a very good database on what model sending unit fits what year and make MasterCraft yet. After asking me if i had a 2 or 3 wire unit, and after having to get back to them the following week (boat and lake house is an hour away from where I live) they then asked me how deep my tank was. Seems there are 3 or 4 different length units to choose from. I told them I'd have to get back to them again the following week. I took a tube of super glue with me and while i had the unit out to see how long it was, I opened it up and did the repair.

                      If you're going to by a new unit, you'll need to know these two things.
                      Last edited by monsoon; 07-21-2011, 08:04 AM.


                      • #26
                        I have a 1993 PS190 and my fuel level sender did not look exactly like the one in the OP picture. In fact, the bottom of the unit was sealed with no way to disassemble it without tearing it apart. So, I ended up buying an brand new MasterCraft fuel level sending unit for 70$. The new one looks more sophisticated in the fact that it is a much narrower aluminum tube. Apparently there is no float inside the new one. Worked very well. Price for a brand new Mastercraft fuel sending unit, 70 bucks. Price for a brand new prostar190, 60 some K. Fixing a 20 year old boat myself, priceless!


                        • #27
                          magnets must repel each other and are placed at ends of float. easy fix as long as the polarity of the magnets is oriented correctly.


                          • #28
                            After seven years, mine broke again. Rather than take it apart and fix it again, I ordered a unit from Wema that seems nicer. Everything is protected inside the stainless steel tube, except the float (and presumably magnets), which have a bit more clearance on the shaft than the float on the last one did inside so should be less likely to hang up.

                            Worked fine so far on the one trip we've done.
                            1998 Maristar 200VRS


                            • #29
                              So how is everyone's repair holding up? My '93 prostar sending unit needs repair or replacement, but I only use the boat 10-12 times a year and I want to fix it so it lasts for many years.

                              Just mostly wondering if the super glue (or epoxy) will last long since it's exposed to gas.
                              I was njskier on here.


                              • #30
                                I was going to attempt the repair but found my sender beyond repair. I ended up buying a brand new ISSPRO 10" unit from for $44 + shipping.