Good job! When the impeller totally fails you can spin that pulley with your fingertips. That moderate resistance kept you from doing a lot of unnecessary work.

DAVIS,
Yes it can be because you are running the pump dry till water gets to it for that reason among others its a good idea to run at least two gal of anti freeze through it (pink w lube)

Interesting...

My 496HO as 200 hrs... Should I perform your test or should I replace the impeller right away?

Just replace it every season and you won't have any problems.

Those Mercury brass pumps are about $500 each plus replacement cost. I would suggest installing the fine sand raw water strainer thats made by CP Performance. It does cost about $400, but its really a life saver when you don't have to loose a pump in the "season" or on a "great trip". It has clear cylinder sides, you can see the debris before it needs changing and it keeps it out of the coolers and the rest of the raw water system. This way the only part of the pump you will replace every few seasons is the inexpensive impeller. Its a billet part that is beautifully made and if you have a 496, you should have this strainer! PS. I am not getting any commissions on these parts and I don't work for CP! HA!

Ray @ Raylar

BTW what is the point of doing this? Sound like useless wear on the engine to me if your not going boating. Although not much it certainly isn't necessary.

Cheap security... Replace it!!

I always did and continue to...