Fuel sensor calibration

[Taxidodger]

Driving a new to me 911 SC and ran out of gas with tank showing slightly less than half. When full, gauge stays on 4/4 and empties at just below 2/4. Can this be recalibrated?
I have removed the float sensor, the float appears to move easily when I tip the tube. I have not dissembled the tube to clean the inside, is this recommended? Any advice to remedy the situation would be appreciated.

[PeteKz]

Yes, you can open it up and clean it.

Did the fuel low light come on? If not, then it's probably internally corroded. You might be able to clean that up, otherwise, get a new sender.

[Taxidodger]

Thanks for the reply. I opened up the sensor, cleaned it although it looked OK and reinstalled it. It worked fine for one fill-up cycle then gauge started flicking wildly once tank started to empty. I have subsequently replaced the sensor, but now the old problem is back. When tank is empty (I drained it) gauge shows just less than half, no fuel warning light. 5 gallons in, the gauge reads half, 10 gallons in, between half and three quarters. Is this a job for North Hollywood speedometers?

[PeteKz]

First test your gauge. If you disconnect the wire from the gauge to the sender, it should go to either F or E (I don't remember which). If you ground that wire, it will go the reverse. Ground the wire to the fuel low light and it should come on.