Cessna 120-140 Association

Hello all,

What is the standard method of removing the Scott fuel gauge from the 120/140? Does it come out from inside the tank? Or can I access it from the wing root?
My LH fuel gauge us getting stuck and continuously shows empty, so I need to remove for inspection/OH.

Cheers

Remove the four screws that hold the gauge in, and it will all come out thru the hole its mounted in. Make sure the tank is empty.

matthewhinmann120cm wrote: ↑Sat Jul 10, 2021 11:59 pmMy LH fuel gauge ... continuously shows empty,

That technically is fine. The requirements are that the gauge must not show full if the tank is not full, and must show empty if the tank is empty. Yours meets those both.

Not very useful, though...

To follow on about fuel gauge removal there was a thread years ago about what to replace the float material with but I was unable to find that a few years later. What does one do in that case, that is what materiel do you use and are there any tips to doing this? I assume that a IA would likely approve this "reconditioning" once a valid technical source is cited.

George

I can’t quote any source, but I would use a cork and paint it with fuel tank sealer after sticking it on the rod.

I’ve owned and flown a few aircraft, and excepting for brand new aircraft about the only truly accurate fuel gauges are the direct reading ones like in our 120 / 140’s.
They are way more accurate than the C-210 I used to fly, honestly about the best fuel gauges there are.

I have replaced several original corks with the Rochester, part number 05-03395, from Spruce. They last a long time. Never had to replace one..

Thanks Randy! I jumped over to AS&S and found out you need to enter "Rochester 05-03395" to get to the float replacement option. Best of all it's cheap for an aircraft part - $3.35 each.

Here's what the back looks like as you pull it out: Spruce also carries the gaskets for our gauges -- it's their Part# 15-4. (Also available from some LP Gas suppliers, incidentally)

And, just a note of caution (from having worked around bulk oil jobbers in another life) -- be wary of static spark potential when removing/installing. There's evidence that gasoline fumes may be much more explosive than the liquid fuel (and, as Randy admonished, be sure the fuel is drained). It's tough to rig any kind of "static bonding cable", but that would be "comforting" .

Mac

Excellent safety point, Mac! That's the reason gas refueling pumps have a ground cable that should be attached to the metal of the aircraft before refueling - rubber tires isolate the structure and cause it to be above "electrical" ground and set up the condition for a static spark/exposition with flowing fuel. Anytime I drain tanks, I have a prepared jumper wire with spring clips on each end for that purpose.

Our modern DIY fuel pump requires one to answer "yes" to the firstt question, "have you attached the ground cable to the aircraft"!

Kinda basic to be reminded here but may save a life! FWIW

2066 wrote: ↑Sun Jul 11, 2021 3:50 pm
Spruce also carries the gaskets for our gauges -- it's their Part# 15-4. (Also available from some LP Gas suppliers, incidentally)

Mac

Again, I went over to AS&S and looked for part 15-4 and was not very successful. Could you be a little more specific? I tried Scott (my fuel gauge brand) 15-4 but as I thought that brand is probably long gone and instead ended up with Scott tail wheels and other unrelated stuff. Is the gasket flat in its original state as it appears in your picture?