Thanks for the rapid feed back, Davec: It is no longer 24V, and I suspect the inst. panel has also been replaced (otherwise fuel and oil temp would also be duff). Some more digging about in Webland gives Pre-April 1989 uses PRC2505 Post April 1989 uses PRC6663 Mine is 1980, implying 2505...

Hello from first-time poster: After diligent search, I'm still looking for some help on the engine water temperature sender. I think the sender isn't right for the gauge. Starts in near the red, then soon climbs through to hit the end stop. True engine temp appears is fine according to the oil...