Reply To: 1972 85 hp V4 overheated…..

[Don]

Well, I think your plastic bag theory is a very good possibility, happens all the time…Once you stop and tilt the engine up, the bag has already dropped away…
And yes, unfortunately, these warning horns usually don’t go off until “it is too late” when running at high speeds. The engines heat up almost instantaneously when something goes wrong. You mention that the powerhead does not show signs of overheat such as burnt paint/melted wiring….I would definitely retorque the heads and exhaust manifold though, especially if you had them off during your repair.
I would pull the gearcase off though, just to make sure nothing has gone wrong. Look for places where the water pump could have sucked air once the boat was up on plane and the water level dropped below the SS impeller plate. You mention replacing the impeller, did you use an OEM piece? Check to make sure the two water pipes are properly aligned and into the grommets properly. Don’t forget those two white plastic tube guides that are usually stuck up on the tubes that will help with realignment.
And, like Bill said, don’t forget to attach a snake to the shift cable before pulling the gearcase down…