Vintage Cars: 71 MGB, voltage stabilizer, moss motors

Question
What is the voltage on the temperature gauge suppose to be around?

Answer
It's supposed to be 10V, coming from a mechanical voltage stabilizer, which often gets noisy or fails. Here is the Moss Motors page for a solid-state replacement (item 7 for your car, assuming positive ground: check that) and the info page about it. If the voltage regulator is producing a problem, you should also be having trouble with the fuel gauge, I think.

http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=29069#top

http://www.mossmotors.com/graphics/products/PDF/131-555.pdf

Given the low price of the reliable replacement, I probably wouldn't go through all the "check before you replace" folderol that the info sheet recommends, but do go to the end of the sheet for installation tips.

Jo