Overheating Problem?

[babs240sx]

I have a 1976 ford 302 in my boat. I had it out at the lake and noticed it was overheating like crazy. My first thought was that the water pump was ****, which I was right, the rubber gear that spins the water was worn down. So I replaced it thinking that must have been it but its still overheating. I searched to replace the thermostat too while I was at it but there is not one on my engine and when I my buddie asked the marine shop they said boats do not need thermostats. Is this true? Sounds like bs to me but who knows.

[CDK]

The marine shop guy doesn't have a clue.
Your engine needs a thermostat to reach the proper operating temperature. "Overheating" can be caused by mud, rust flakes, plastic, weeds, a defective circulation pump or a bad temp. gauge.

[FAST FRED]

the rubber gear that spins the water was worn down

If bits pieces and chunks were missing , you have to back flush and get them out of the engines cooling passages.

Check the timing , too much advance (worn points) can cause too much heat.

FF

[Carteret]

There is also the possibility that there is air trapped in the top of the engine that occurred when the coolant system was opened. I like to place a plug or a petcock in the top of the engine near to where the thermostat housing is, (usually) drilled and tapped on top of the t-stat housing to bleed off air. Fill and bleed before starting the engine and then again soon after start up. If you wait and bleed after the engine is warm the steam that usually escapes (air hot water mixture) can be quite painfull.