Ok still working on our 76. What if the water temp. sensor and the thermal time switch are hooked up wrong? What I mean is if they are switched. I replaced the Temp sensor and I think the wire running to it has the red tape on it. And i think it should be the other way. with that wire going to the Thermal Time Switch. What it still will do is run ok until it gets real warm then stumble at 3000 RPM.

Check the plug that goes into the cold start valve against those two sets of wires for continuity. The ones that show continuity with the cold start valve connector goes to the thermotime switch.

Ok that's right why did i not think of that so dumb.Thanks

Would it run if they were switched?

Yes but it would be hard to start in cold weather because it wouldn't be getting the 'signal' to open the cold start valve and it would be too rich when it reached operating temperature since it wouldn't be getting the proper 'signal' from the temp sensor.