I have just had my old 55hp evinrude serviced and tuned and it now runs great, except for the fact that it overheats very quickly. The tell tale flows okay (not great but okay). We investigated the thermostat only to find there was none! There was water flowing out of the hole where the thermostat should be, but I'm not sure if it was a good flow or not as I'm not that experienced. I pulled the pump apart to have another look and it seems to be okay. I gave it a good flush in both directions. The bloke who serviced it is retired and is reluctant to pull the engine apart. He thought maybe a faulty gasket/seal was letting in exhaust and blocking the flow around the engine. How do I know if this is the case? Any other possibilities?
