Gordon - I love the 2a. It reminded me of The Spanish Inquisition
"There are two points to consider - 1, the bell crank. 2, the crankcase pressure leak. 3, the dipstick sensor. There are three points to consider.."
1. Thanks for the info - FWIW the bellcrank throttle linkage works fine and I'm completely happy with it. Easy to maintain and tweak.
2. Good point, well made. I will endeavour to follow your advice on this.
2a. I've not traced all the wiring on sensors etc to give a definitive answer, but I know when I wired up the disptick the wrong way round the temp gauge immediately went to max as soon as I switched the ignition on. Once fixed, the gauge worked ok. I'm sure there is another sensor somewhere. I presume this might be it?
I'll remove the dipstick and test for a current in a boiling cup of water.