1970 Johnson 40hp hi temp light.

Hi there, this is my first time posting but have been lurking for a few months since i got my first boat. I have a 1964 MFG Niagara with a 40hp Johnson electric shift. The boat has not seen water since 2000 and likely the motor hasnt ran since then either. I bought a new water pump impeller, carb kit, points kit, and coils along with some fuel line to get her going again. I wanted to see if it would run at all so I cleaned the fuel lines out with fresh gas and squirted some gas in the carb and it fired right up. I had it in a garbage can full of water but didnt see any water coming out while running. I had enough water in there to submerge the water intake. After a few minutes of idling the high temp light came on and I shut it down. I thought I had heard that the high temp sensor was a one time deal that melted together to make the connection then it was junk? Not really certain where this sensor even is. Any suggestions as to other parts I should replace/check before putting this boat in the water? Thanks in advance for the help.

Re: 1970 Johnson 40hp hi temp light.

You'll have to get it in deeper water. About the same as if the boat is in the lake and just idleing. The high temp sensor is not junk and should be on the cyl head.

Re: 1970 Johnson 40hp hi temp light.

I had it in the barrel deeper than it would be if the boat was in the water. Pretty sure the water pump impeller is shot but do have a new one sitting on the workbech.