I am seeing wear on the impeller and housing that looks like cavitation to me. I have never gotten the wear - time or running hours from impellers I think I should. I usually replace every 100hrs at the most. Average 2 impellers a year but usually less then 100hrs running. Last impeller has 50 hrs run time. About 20 hrs with mufflers shut (teagues) and 3500rpm which I know puts back pressure on exhaust and I am assuming water pressure in the block. Never checked it. Anyone with high water pressure and or cavitation (AIR) experienced the wear in the pics posted. Hope they come through.

I have also never had an impeller split at the end of the vane as this one did. Always down low in the bend prior.

I thnik I will try Globe Blue impeller next time>

Paradigm shift
I would replace the housing. The wear mark looks like it was caused by corrosion or a stone. If the housing is not smooth the impeller will be torn up as soon as you turn the engine over. Just my 2cents.

Thanks, guess I should of added that this was a new housing and I have seen this wear (pitting in same area) on housings pretty much every time. I have been replacing housing and impeller as a set. Scratches are from me sanding out the sharp edges. Unbelievable how rough housings are sometimes at parting lines.

You can actually see on impeller where it split and on the vane behind little round dot that is on all the vanes. These are a first.

I have a times had to sand the edges of the ports in the pump housing. Seems like they are always sharp with flashing when molded.

I Guess I Do Not Understand The Problem. You Should Be Changing Your Sea Pump Every 100 Hours. I Do Not Believe In Just Changing Your Impeller Only, Because I Guarantee You That I Could Almost Always Find Something Wrong With The Housing. I Would Only Just Change Impeller On My Own Product Not Customers. Plus It Does Not Take Much Crap To Go Through Pump To Tear It Up. The Longer It Sits Without Use And Stays Dry Is Also Worse For It.

Also, When You Rebuild Them Are You Properly Lubing Them For Dry Start Up? Soapy Water, Or Some 2-4-c Lube. I Know, You Are Not Supposed To Use Grease According To Mercruiser. But The Water Washes It Away So Quickly You Will Not Have A Problem With It Ruining The Rubber. Guaranteed! Experience Is Better Than Manuals At Times.

rock hard thanks for your input.

I usually do not make it to 100hrs before changing. I really do not like to do it on the water so I usually change them sooner. Like I posted I always change both housing and impeller. I just do not see why this impeller is split on the top of vane this time and was curious if others see the same wear. I just think it is from air - cavitation inside pump is all. I always lube prior to assembly.

As for damage from stuff running through the pump I would say sand is my biggest issue. But always wears in the same area with no other damage any where else as for the housing so I do not believe it is from trash.

Maybe I need to come up with a better mouse trap if I want to run longer without changing impellers.

At higher speeds you may be drawing the inlet hose closed and cavitating the up-make sure they are firm and well reinforced.

There's not much to add to what's already been said. Raw water pumps work in a harsh environment. I've always seen localized wear at a couple of spots in the housing just due to the way the pumps operate. I didn't hear any reference to using a sea strainer which would minimize the debris. My first reaction was that sand was probably a factor. Personally, I would never go more than 100 hours before changing impeller and housing (kit p/n 46 807151A14).If it's your boat and it has twins, you may see a drop off in water pressure in one motor when running at a consistent rpm. I watch mine like a hawk.

Well I reread my first post. I replace at least every 100 not 200 hrs. This one had less than 50 hrs.