@Ronnie thanks. Not a thorough response but cavitation as I understand and have seen in the industrial world do to pumps. As far as our boats, I have had cavitation pop up a time or two on mine. Let me define what I have seen and currently am dealing with and how I plan on fixing it... When I floor both engines wide open. My right engine tach hits 8500 and bounces due to the rev limiter. The left engine hits about 8000 rpm and holds until speed comes up. My right engine is slipping or cavitating. If I back off the gas slightly, I can hold revs at 8000 until I come up to speed. I would define this as slight cavitation, but it is happening. It is pretty easy for all of us to define when you have an engine full of salad, that's bad...
The first thing I look for is loose sealant. My OEM sealant looked like silicone. Silicone is a good gasket material but does not have any adhesion properties. We want to have minimal but some adhesion to what ever material we use to seal the pumps with, because you will likely want to remove that thing some day and a super adhesive will prevent easy removal. Anyway, if there is any loose sealant, it can cause those low pressure zones through the turbulent flow and cause cavitation.
Now when I say loose sealant, I have seen it where the silicone looks fine visually but if you push on it, you can tell it is not adhered to anything as it is loose on the edges. Last time, I dug out this sealant (note that I did not remove the pump) carefully and had a trough or gap to fill. I just did a smoothed over top coat that filled in the gap with new sealant. Problem went away and no cavitation.
Now the argument of what sealant to use. Again another topic where every %$#@! has an opinion of the right thing to use. I researched a bit and centered in on a vulcanized rubber gasket material. I used Permatex The Right Stuff gasket maker. Available at a fine auto parts store near you. I did basically a caulking job and smoothed it over flat with my finger and let dry.
The same engine I repaired this way 3 years ago is giving me issues this fall. I will see if it is a new spot that failed or my old repair. Either way, if I get 3 years out of this type of repair (and don;t have to pull my pumps...) I'm good!!!
Sorry I don;t have pics. I hope my long winded explanation of how I fixed it helps. If I am thinking, I will try to get pics this fall. I know, I know... pics or it didn;t happen
Good luck!!!