OK, the first startup decimated my impellor. I've heard of the housing getting scored and needing to be replaced. Here's some pics of the housing. How does it look? Should I just pop a new impellor and roll?

I back flushed all the way to the oil cooler. I don't think any water was getting past the pump anyway so I don't think debris will be an issue.

http://www.offshoreonly.com/forums/g...e-shock-3.html may be someone will know what part number,,the front halh of the jabsco pump is,,,,for me it would depend,,how much room and time it takes to get the old pump off,,,if its a pain replace with new

You may get a small loss of pressure at the scored cover, but the body looks fine so I would just go for a new impeller.

What is the procedure for backwashing? Also, what is the best way to remove the pump/replace the impeller? seems like a ***** to get to.

I disconnected the raw water hoses in several places and flushed using a garden hose.

As far as removing the pump, that depends on how much room in your engine compartment. I think the easiest way to do this is remove (see link) bolt #15. Then disconnect the input and output hoses, and the sensor #12 and pull the whole pump.

http://www.mercruiserparts.com/Show_...=Seawater+Pump

I figured that out after removing all the bolts around the housing.

Thanks Ted! You talked me into it! That's what I'm going to do. I'm not liking the sound of $350 for a new pump.

Just a suggestion here, but you guys back in the east and north who layup and store for long periods during the late fall, winter and early spring with 496's.

Take out you impellors on layup and don't re-install them until spring fit out. If the impellor is obviously bad at removal, replace, if not re-install in spring and go! Its the long sitting dry periods especially at low tempersatures that decimate the impellor rubber.

This will prevent the impellor grenades at startup and keep all that housing damage to a minimum and the debris out of the cooling system. Just a thought.

Best Regards,
Ray @ Raylar

Are you flipping kidding me!! I almost ripped the skin off my arms removing all those bolts from the housing!!!!
Thanks for the info!!!

Great tip Ray!

I think I mis-quoted slightly. There are 3 bolts ( the 3 longer bolts) that hold the pump on. #15, the upper left, and the middle right bolt.

It's a knuckle buster for sure on most boats. I took me about an hour to get it off. Getting it back on was a fight too.

I can't understand why a part that need to be changed regularly has to be so hard to get too.