Reply To: 67 33HP Evinrude running very hot

[Don]

Well, I guess anything IS possible.  At this point, I would like to have a closer look at the exhaust hsg cavity where the little bleed hole dumps into.  Where does this cavity lead to?  Is there a passage from this cavity into the upper part of the exhaust hsg that should help cool it?   Take some more pictures of the exhaust hsg and that cavity.

Like Frank says, an air/exhaust leak into the water pump could be to blame, but it doesn’t seem as though the powerhead is actually overheating, although you haven’t actually checked with a pyrometer yet.  It is easy to pull that side cover off (provided the screws will come out) to check for the crack Franks pictured.  May as well pull the gearcase off to have another look at the impeller/hsg and the mating surface below it.   But, I’m remembering that you said it had good water flow, so that pulls me away from the air/exhaust leak into the pump theory a bit.  Although it would still probably pump well at low speeds because that area is under water, even with an air/exhaust leak.   Looking at the pump discharge at high speeds would give a better indication.

Finally, there is surely the possibility that this engine is cooling “normally”/as designed, and that exhaust hsg area just normally gets hot.  I suppose we could consider adding a cooling bleed hole somewhere if none is to be found.  But, we must be very careful to avoid re-engineering the wheel and creating other problems.  I just wish I had some of these style engines laying around to tear into, but don’t…

Finally, please use new gaskets when you reassemble, don’t mess around with the old ones, even though they are almost new, especially the head gasket.