Water pump fail - Did I kill the motor?

johnnygjr said:

74Merc50, Is your anti-Ventilation plate level with lowest point of the bottom of hull?

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I seriously doubt this has anything to do with the motor position. It's been running just fine for 44 years in this configuration. No PTT.
This was prob an issue with improper impeller installation and/or lack of any initial lubeage. It was likely installed in reverse and just tore itself up within an hour. Sounds plausible to me.

Occam's Razor - The simplest solution tends to be the right one.

I'll answer this topic out with good news; the motor is not dead.
Just took it out on the water for a 5 mile cruise and the pee hole works at idle, full throttle and all points in between.
There is no loss of power, still gets the super sport up to 30 mph., downstream...same as that prior to overheating.
Took off the cowling back at the dock and the power head was cool enough to touch and hold, like a luke warm cup of coffee.

If you want something done right, do it yourself.

If you want it done wrong, go to my local dealer shop, Sport-o-motive in Appleton, Wisconsin.
Pretty sad because they used to be a great dealer and that's where this boat was purchased 44 years ago.

Hate to say it, but millennial mechanics ruined it. No pride in their work and zero responsibility. No customer service skills. Lesson learned.

Have fun and be safe on the water!

Oh more follow up...
I would like to get some verification from a professional old school outboard mechanic on what appears to be a motor that won't run itself to death when it overheats.
Either the German engineer was so smart as to figure air flow vs heat density of fuel and air mixtures and just designed in a heat choke point or there is some other unique overheat design going on with the carb. The following was one"professional" sounding reply....

Motor was seizing up or running with other issues.-----There is no warning system / horn / shutdown system of any kind on that motor !!

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Motor wasn't seizing. Runs like a champ again.
The only thing that made it run no more than 1500rpm was excess heat...but how? Just the dynamics involved would make it a mechanical heat control. Maybe it was just a design accident, I doubt it.

Good luck with your motor.