Here is a post I made recently in regards to my Velocity 260 Impeller. What a pain in the a$$!
http://www.offshoreonly.com/forums/v...496-260-a.html

Hey guys:
I know taking the raw water pump apart on the engine down in the bilge in that tight spot is a ***** on may boats.
I would reccomend taking of the serpentine belt, removing the two 10mm nylock bolts that hold the raw water pump bracket to the front of the block, loosening the hose clamps and the two hoses and pulling the whole pump and bracket off to the front. You could then easily remove the impellor and in spring re-install the pump and bracket complete.
Merc did not engineer this pump and location with the poor wrench in mind obviously!

Just a thought.

Best Regards,
Ray @ Raylar

I replace my impeller last year and had the same problem with the scoring on the housing. It did affect my water flow. I noticed that there was a little less comming out the exhaust. I replaced it with this kit http://www.jcmarinellc.com/water_pump_kit.htm
Good kit and easy to install. I noticed a difference even on the hose. Can't wait to put it in the water.
Rob

Ray's removal advice is right on. Take the ENTIRE bracket off with pump attached. WAAAAYYYY easier.

I can do two motors in a little over an hour.....with only about a foot of clearence in front of the motors.

Once again, thanks Ray!!

Has anyone used the blue "run dry" impellers? Just wondering if they last longer?

I have the same pump on my 6.2 and I pull my pump and replace every other year, my housing looked exactly like the one in post #1, I simply machined it down and made the outside housing smooth again, and yes how bout you guys changing this pump in a donzi classic 18? It is no 30 min job to say the least, battery, manifold, riser all come out and it's still a PITA! However my water pressure did rise after smoothing out the housing, if it looks worn next time I replace the impeller I'll be installing a strainer.

Agree, Just lay it up on a 12" sander and grooves are gone. Thats the quickest way and works well.

If the pump body is'nt to scored inside, sand the back cover on a belt sander. but be very carefull not to grind too much on one end.