Sounds like the Voltage stabilizer on back of speedo has carked it.
These things are just a vibrator (ooooh, stop it.. ) and supply 10V to the fuel & temp gauges.
If it's shot, do what many of us do- PM `wombat' for an electronic one.

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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.

Electronic ones are very easy to build if you are handy with a soldering iron.

It takes about 3 components and will cost you about $3 from Dick Smith or Jaycar.

You want to ask for a LM7810 or LM7809 regualtor (10v and 9v versions respectively). In the TO-220 packaging.

Tell the guy at the counter what you are doing and he will know what to get.

You will also need a couple of capacitors.



The 780x IC will look like this:


Pinout is:
1. Unregulated voltage in
2. Ground
3. Regulated voltage out

Make up a little case for it or use the old one, and bobs your uncle...

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"Life is not like a box of chocolates... it's more like a jar of jalapenos. Whatever you do today, may burn your arse tomorrow."

There are 2 terminals in the boot that go into the fuel tank sender unit. Just make sure they are still connected as I have done that before...

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Lillee - 1969 Morris Mini K

Are the early minis (ie the one with the voltage reg hanging off the back of the speedo) the same voltage? I seem to think that they used 5 or 6 volts? Might be my dodgy memory playing up though....

I just rebuilt my fuel sender last night. I'm supposed to get a range of 19 to 245 ohms as the float goes from full to empty. I am only getting 19 to 200. I'll pulled it apart and re-wrapped it with 245 ohm length of resistive wire. I also cleaned it up while I was there.
Instead of a float, I found a large cork used instead. At least it won't sink.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Wombat's ones have no caps, they just have 3 flying leads with spade lugs.
No case needed.
They work fine, I'm running one in each car.

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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.

The 7805 puts out 5 volts - you need 10. From my searching no one in in Oz stocks the 10 volt regulator - I get mine from overseas. You can use an adjustable reg -as per my MK1 version which the Dr has the only one made the MK2 version uses the single 7810. Price is $15 posted

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

Geez you guy's are good!

I was set to build one 'till I read wombat's post.
Will contact "the peoples prince" later if all else fails.
$15 sounds reasonable, but we'll have to see what the Minister for Finance and Social Functions says - lol.

Cheers

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"Why mini? 'cause it's got the edge."

Just let her run out of fuel in the mini , she'll jump at the chance to fix it for $15 ....

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haha

good to see people coming up with a solution to a CHRONIC mini problem, the ol' fuel gauge mystery

.

Yeah, I couldn't find any in Australia so I got what I thought were the right ones from the US.
They're marked as UA7810C but they always overheat when I tried to use them so maybe I didn't get the correct type or I'm doing something wrong.Still have 1/2 dozen left.
In the end I brought a kit from Jaycar which seems to do the job ok so far.steady 9.9 volts.
It hasn't fixed up my problem of the fuel gauge not reading more than 3/4 when full.

that could be a faulty float

Anyone tried one of these?



Looks suspiciously similar to the original, looks the same as the one on the back of my S speedo. not sure what the voltage out is.

http://www.minispares.com/Product.aspx?pid=35969

Which models used the lower voltages?

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.