Originally Posted by Snipe
I personally have not experienced the problem. I just bought the boat and will have to wait until next season to see exactly what the gauge says. The PO told me that he would fill it up and the gauge comes to half full. That makes me think possibly he used the 10% Ethanol and there may be some corrosion on the sender. My previous experience is with a sending unit in a Correctcraft that has a type of rheostat that can rust. I'm assuming that this is not the case with the units Matercraft uses. I will give the guys at Midwest Mastercraft a call.
Thanks for the replies.
Not usually corrosion on these senders- the magnets release from the float or the float foam can swell. Get access to the sender and turn the key on, then connect from the pink wire to the black. If the needle deflects to Full, your gauge is fine.
In this case, you can file a little off of the slots in the float that were binding and make sure it slides to the top without hanging up. I used a file that's just a little thicker than the board in the sender. If it lost one, or both magnets, you'll need to remove the sender, remove the round plate on the bottom and remove the float/magnet(s) that fell off. Position the magnet(s) in the float and turn the key ON, then slide the float from bottom to the top, making sure it reads correctly. You may need to reverse one of the magnets. Use Super Glue gel to keep it in place.