Indeed the impeller housing can be worn with grooves in it. Also check the wear on the front plate. I believe these are reversible but new plates are also available for cheap.
Indeed the impeller housing can be worn with grooves in it. Also check the wear on the front plate. I believe these are reversible but new plates are also available for cheap.
Do you have a sea strainer? If not the transmission cooler may have some blockage.
Check the belt, too. Could be slipping.
The housing is smooth. I'll check the strainer again and I'm gonna replace the belts if only because I can't remember when I last did so. They look fine, but there is some dust. Had one snap years ago. Quite a noise.
The lake is up, and full of debris of all kinds. Thanks again for comments.
Once you confirm that you have good water flow and that the thermostat is opening, the only other thing it could be is that your raw water pump is due for a rebuild. I chased this problem around on my 1987 for about a year before I rebuilt the water pump. Fixed the problem immediately. I never knew that they had an expected service life.
Former owner of a 1987 Supra Saltare. Current owner of a Malibu 23LSV.