Datsun Roadster Forum-311s.org

I've got a '70 2000 with the stock fuel gauge, tank, sender... Mechanic recently redid the tank to get the rust out of it, but since I got it back, when the tank is filled, the gauge is reading as 3/4 full. If I can ask, is this something to do with the sender/float or can it be adjusted on the back of the gauge itself? Otherwise the gauge seems to function properly.

Yes, there is an adjustment on the back of the gauge for "full" and "empty" positions.

JT is correct on the gauge adjustment. Prior to doing that, try grounding the sensor wire. If it swings to "Full", the problem is likely in the sending unit, which would be suspect anyway, given that you just had the tank serviced. (The sending unit can be cleaned CAREFULLY.)

And how would you carefully clean the sending unit? Could you soak it in EvapoRust then wipe it down or use a toothbrush on it?
Linda

Probably as many strong personal preferences for a particular cleaner as for penetrating oil. If the sending unit is bad order b/c of rust, EvapoRust or vinegar can be used. Mine have always been caused by gummed fuel deposits, and this product has produced good results for me (when brushed on full strength with the sender out of the tank):

https://www.berrymanproducts.com/produc ... p-t-f-s-c/

Honestly, the list of precautions is so long that anyone who is doing this for the first time may well be advised to purchase the following (and be done with it!):

https://www.datsunparts.com/1366

I getcha John, that SDS is long and scary!

JT68 wrote: ↑Fri Oct 16, 2020 5:50 pm Yes, there is an adjustment on the back of the gauge for "full" and "empty" positions.

Thank you!

jhayden wrote: ↑Fri Oct 16, 2020 8:13 pm JT is correct on the gauge adjustment. Prior to doing that, try grounding the sensor wire. If it swings to "Full", the problem is likely in the sending unit, which would be suspect anyway, given that you just had the tank serviced. (The sending unit can be cleaned CAREFULLY.)

Gotcha, much appreciate the advice.

Question......is the "empty adjustment only to be done when the tank is actually empty and voltage is going through the sending unit ? Or can it be done with key off, and no voltage to sending unit ?

Mine is an early '67, but after Jon Frampton restored my gauges, I adjusted my fuel gauge so the pointer just touched the upper, right end of the "E" , while there was exactly 1 1/2 gals in the tank. The key need to be "on".
YMMV (Your Mileage May Vary !...get it
Mike