Do I have the correct sending unit for my tank?

[turnjare]

Hi Everyone,
I'm trying to decide if I have the correct sending unit. The truck is a 1949 with a frame mounted gas tank. The fuel gauge reads half full when the tank is empty. I thought it was because i am converted to 12V and that I needed a voltage reducer to continue using the old gauge, but now I think its something else. The travel on the sending unit is 13 inches and the depth of my bed mounted tank is only 8 inches. When I took out the sending unit and tested it, it read empty on the gauge when fully extended to 13 inches! great news, I don't need a voltage reducer. The bad news is that it seems that I need a sending unit with a shorter travel so I can use it in a 8 inch deep tank. Are those available, or should I try to modify (bend) the one I have? Does anyone have a pic of a sending unit being used in a under bed mounted tank?

Thanks

[mr48chev]

Why not modify the existing sending unit to work with the tank and read correctly?

You have too possibilities for correcting it and may have to use both.

1. The pivot point for the float arm needs to be at a depth in the tank that allows full float travel both to the bottom and the top to go from empty to full.

2. the length of the float arm needs to be correct to allow full float travel. A longer arm is going to reduce the total degrees of swing of the float while too short of an arm won't let the float go to the bottom or top of the tank or close enough to read correctly. On that If it were me I would want the float to end it's travel about a half inch from either the top or bottom of the tank.

Scroll down this page a bit and he did a drawing/demo using an actual float that shows pretty well how one should be set up to work right. I can't draw pictures that match what he has using the actual float. https://www.hotrodhotline.com/instal...r#.VZ3lk_kTprR