Has anyone ever adjusted the gas sending unit to read correctly? When full the gage registers 3/4.
Its in a 63 F-100

 

I haven't adjusted it but currently I have mine out, I don't know if it can be adjusted at this time. If you do find out let me know please.

CB

 

I suppose that it's possible that the arm gets bent, but I have yet to see one that needs adjustment. The usual problem is that the electrical contacts are bad (I think it's called the reostat) or the float has a hole and gets heavy.

<FONT COLOR="#ff0000" SIZE=" 2" FACE="Bassett">Stock Man</FONT>
<font color="#0000FF" size="2" face="Graphite Light">1967 F-250 FE 390 4wd LWB Styleside</font>
<font color="#0000FF" size="2" face="Graphite Light">1966 F-250 I6 240 2wd LWB Flareside</font>
<a href="http://www.hometown.aol.com/tbeeee">http://www.hometown.aol.com/tbeeee</a>

 

Stockman is correct- the sending unit works on a rheostat, or resistor of sorts. The guage registers according to the amount of electricity running through it.

If the guage measures 3/4 when it is full- does it still have about 1/4 left when the guage reads empty? If so,the problem is mostlikely mechanical: the rod which holds the float is probably bent, or you have a sending unit that is not for your tank originally (I am assuming that you have the original tank here.)

If it measures correctly when empty, your problem is most likely electrical rather than mechanical. (Not a guarantee, but that's usually the way it works). The wiring hook-up is simple- there's one wire which runs over the driver's door (orange in color as I recall). Check it , as well as the connections at both ends. Cleaning the connections or replacing the wire - or even cleaning the contacts on the sending unit- should do the trick. Sometime those sending units get gummed up.

Do be sure to check the float as Stockman recommended. the one in my 64 had a hole- so I robbed one from a 59. Most of those old floats will work. The 59 float is longer than the 64 (and 63), but the diameter is the same, it clips into the sending unit perfectly, and it works right.

It might also be that there is something in the tank, hung up on the sending unit and holding it down. I dumped a pocket knife and a muzzle-loader ramrod out of one of my tanks!

Nate

1964 F-100 Custom Cab 292 V-8 3 spd
1964 F-100 292 V-8 3 spd
1990 F-150 5.8L

 

Stockman is correct, I had the same problem with my 71 sending unit.I removed the sending unit then carefully took the side cover off, yours may or may not come off, after inspecting the rheostat windings I found them to be corroded. I cleaned them up the best I could being very careful not to mark or distort the windings,then I took a toothbrush and scrubbed them with dialectric grease then wiped them clean. Then clean up the contact arm that rides on the windings,use the finest sandpaper you can get [600 wet or dry is what I used], you dont want any rough surfaces as it will act as a sandpaper to the windings. After putting mine back together it works perfect,good luck with yours.

" bowties in the rear view mirror PS. I also replaced the float as long as I had it apart.

 

OK, thanks to all. In the ten minutes it took to take out the unit, clean it, bend the stop, and check the unit, I now have a full tank when full....