Fuel tank sending unit and gauge and grounding

[03232001]

My fuel gauge has never worked in the 12yrs I have had my boat but I unfortunately had to take up the deck over the tank so while I got it apart I want to see whats going on. I have only three wires going in that direction. One goes to the sending unit,One goes to a welded tab on the tank(I'm going to assume ground), and the other goes to the filler neck(I'm going to assume another ground). Does a sending unit like this actually have power going to her or does it register resistance. how do I test it and if I had to replace it are the floats inside adjustable to be made universal for different tank sizes. I have a stainless steel tank, copper fuel line to a stainless ball valve then rubber line to motor will the grounding wire to the tank alone stop anode corrosion. Or do I only have to worry about that for metals actually in physical contact with the salt water. and last I am a little bit of an over doer sometimes and I'm always worried about dirty fuel in all my toys (Motorcycle,dirtbike,4wheeler,jetski's,)I have a Johnson on my boat with a VRO pump, after the ball valve I have 2 separate fuel filters and a water separater in line plus the filter under the cover of the outboard. Is there a point where I may be concerned that the pump will not have enough draw to pull fuel. Thanks for any input

 

[dockwrecker]

Re: Fuel tank sending unit and gauge and grounding

A bit of over kill on the filters, one with a water seperator is more than enough with regular maintenance. Pump pressure may suffer as you suspect.
As far as the tank sender goes, yes they measure resistance and your assessment of the wiring is right. After pulling the sender out, measure the top to the bottom of the tank where it lives. Universal senders have instructions of how to adjust the float height, it's the float rod length you have to fool with, no big deal. They're cheap enough, just get another one, don't bother with trying to rebuild the one you have.