I have an 85 Supra Saltare with a Chevy 454 PCM engine that is overheating.

I have replaced the impeller, thermostat, water pump and hose between pump
and thermostat housing and it still overheats.

This boat for the last 2-3 years always runs between 125-150 degrees. It
doesn't seem to get hot at idle speed, but as soon as you accelerate within
60 seconds the temperature shoots up to 190.

I will put it out of the water soon to check for exhaust blockage, but is
there any other common problems I should look for ?

Thanks

Saltare