1972/1973 70HP Chrysler overheating

[Kendegreat]

Hello,
I bought two Chrysler 70 HP motors, one is a 1972 and one is a 1973. Both supposedly run... However I using parts from one to fix the other. Anyway, 70 HP Model 707 HE is running and I replaced the Impeller. How ever after just a couple of minutes the overheat horn sounds. No water is coming out of the hole like it suppose to. It did at one time. I replaced the impeller with another new one... same thing. I was thinking maybe the Thermostat is not working and is closed. The SELOC manual says that there is four bolts holding the cover on. I can't find it. However I do see where one might be.... but I would have to take off the cover over the cylinders to get to it. Is the thormostat right above the Number 1 plug? Any suggestion on what I can do? Where can I find Gaskets and a thermostat?

Thanks,
Ken-De-Overheated

 

[eurolarva]

Re: 1972/1973 70HP Chrysler overheating

This is a newer motor but it should be in the same place. Follow the red arrow

 

[swrupert83]

Re: 1972/1973 70HP Chrysler overheating

something i just found out with my 85 HP don't know how you're feeding water to you engine. I first tried to use ear muffs and I didn't get any water coming out, but then I put the engine in a 60 gallon tub deep enough to cover the Cav plate. low and behold the water pump started working. worth a try

 

[Frank Acampora]

Re: 1972/1973 70HP Chrysler overheating

First, when using muffs, the water pressure and volume must be high. You need to have water spraying out all around the muffs to ensure enough pressure to prime the pump.

Second, on some of the old three cylinder Chryslers, the thermostat did not have a separate cover. It is necessary to remove all the head bolts and the three 7/16 head 1/4 X 20 bolts (one may be the temp overheat sensor--5/8 head) beside the plugs, then remove the head cover to access it. You will see the odd shaped bump that houses the thermostat above the top spark plug. --Anything to make your life difficult.

I don't remember exactly, but I don't think the cylinder head cover has a gasket; some did, some didn't--you just use permatex. The thermostat can be found over at The Chrysler Crew.

 

[Kendegreat]

Re: 1972/1973 70HP Chrysler overheating

Thanks,
Pulled it apart and ordered new gaskets and thermostat... Hope that does the trick. Is it norl or the top piston to look so carboned and then the middle one half as bad and the bottom one looks great? What is this a sign of?