Gday!

My temp gauge doesnt work. when i turn the ignition on, the needle wobbles and settles on 0 (i assume this means there is power getting to the gauge) but doesnt move from there.

has anyone else had this issue? could it a problem with my sender, or is it time for a whole new gauge?

cheers!

Turn ignition on. Go round the front, pull the sender wire off and hold it onto the block or a head stud so it's grounded.
Have somebody watch the gauge- if it reads H the gauge and wiring is OK.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

And if it stuffed I may have another one for sale .

_________________
That's why it's good to be.............ME

How do you check if the sender is working though? The gauge might be fine but the sender reading low when it is actually high.

If it goes to H when the sender wire is shorted, but doesn't work when connected and motor hot, the sender is stuffed, 99% certain.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

my understanding (and i'm very open to corrections here)

is that an electric temp gauge is an earthing device...

when cold no earth, no current flowing through gauge, no reading.

as temp rises, amount of earthing rises, more current through gauge, higher reading.

i'm remembering some term like thermo-conductive metal.... but i may have just made that up.

So... take your sender out of equation if you earth out wire, you should get stupid hot reading... therefore identifying sender as broken. if earthing out wire doesnt change anything then by your powers of deduction your gauge must be the problem...

of course this is all assuming the power supply to the gauge is all good...

I was more concerned that the sender (not the gauge) may be saying "warm" when the engine is actually "hot." Do they un-calibrate over time, or is just a work/not work thing?

They usually work/not work. But, there were about 3 different senders used over the years.
One of my heads has a black ring one, the other red. No idea of part numbers but both read the same on my Minimatic/Mini K temp gauge.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

There will be a number stamped in GTR 101 or like that, if it is still readable, to distinguish the different types.

_________________

Senders work or don't work. No in between.
There are two gauges and senders for a mini but as the 1st is pre-64 for semi conductor gauges (fast moving pointer & no regulator) and these were only in cooper's it is highly unlikely you have the wrong one.
Earthing the gauge will tell you you have continuity to the sender but will not tell you about calibration.
It will finally get to Hot as Temp gauges have a negative temperature co-efficient (High Resistance 250 ohm cold to Low Resistance 19 ohm hot in the case of Smiths Bimetal)
The fact that the pointer moves up scale slightly at the start would suggest that the gauge and regulator are ok. It is still possible that the span (calibration) of the gauge is out.If the regulator is high (over 10volts) then the gauge will read high.
End point sounds like the sender is u/s.

Try the earthing trick, i used to do it all the time at work when we did instruments but be careful.
As the Doc said have someone watch the guage, it will move fast and if left it will be cooked, so if it flies up to 1/2 in a couple of seconds thats ok - take the wire off.

My temp gauge doesnt work.
Is your fuel gauge playing up as well.?