1961 350 4cylinder temperature gauge

[nathanglasgow]

Can anyone offer any advice on how to,where to and what to fit a water temp sensor to a 1961 350 4 cylinder merc thunderbolt engine.After replacing the impeller and water pump cover and top plate the motor cools great ie at 2/3 throttle for 2 hours in a test tank(3 gallons used at almost $10 the gallon here in Scotland) the exhaust cover is cold and the sides of the cylinders and cylinder head is warm/mildly hot to touch but no tell tail stream is present.I would like to fit this sensor due to the lack of tell tail.I have done the usual things in trying to get the motor to shoot a stream of water from the tell tail(back flush,airline,poke with wire ect)but no joy.As the motor obviously is cooling adequetly and i cant be bothered with the time or hassle of pulling the powerhead(remember any parts for this motor i have to import from the USA and i got it for almost free) fitting a sensor would be cheaper and easier.The motor does not owe me much but it would be nice to offer it a fighting chance at least of surviving as it is already 47 years old.Cheers from bonnie Scotland.Nathan

 

[Laddies]

Re: 1961 350 4cylinder temperature gauge

I am all most certain that if you look on the port side in the area that the nuts that hold the powerhead on come thru the torque tube between the back two on the port side you will find the pitot hole the are quite low and plug easily. As far as a temperature gauge sender there may be a 1/8 pipe plug in the top of the powerhead near the exhaust cover, it was there on some engines for a water pressure gauge. if not it could be drilled Mercury opted for a pressure gauge over a temperature as when there is no water in the block the temperature sender won't function and a pressure gauge will.