Wally

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Well since i bounce around on the net reading all different forums i sometimes forget where i post things. Seems i didnt post this guide on changing impellors so for everyone that wants to DIY or is curious on how the marinas do it for you, this post is for you heres our donor boat, a 2001 Powerquest 380 Avenger with twin 500efi's. The starbord side impeller is original with 142hrs on the clock and needs to be changed. The port side was changed during a poker run in FL

Wally

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the tool we are going to need for this project are:
1/2" box wrench
5/8" box wrench
1/2" sockect on a 3/8 drive ratchet
flathead screwdriver
some rags
and 2 zipties

First thing we are going to do i locate the seawater pump. In this case (and just about every other boat out there) its on the bottom left when facing the engine. (pic#1)
so we now need to get the belt off the pully. The tensioner pully is the black pully just above. Take the 5/8" wrench or socket if you want and just loosen the nut. No need to take it all the way off as you will see when you start it drops almost right away. Move the belt to the side so its out of your way.

Wally

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In this case theres a mechanical fuel pump on the pump. So we need to unhook the fuel lines from the pump going to the filter (5/8" box wrench) and the fuel line supply to the pump (flat screwdriver). This is were you need the rags!!! You will also need to unhook the two water lines off the back of the pump.
******Make note as where each one goes to. You mix them up and you WILL ruin a brand new inpeller on startup!!!*****
And when you have done all that you will need the 1/2" socket and drive to loosen the 4 bolts that hold the pump to the bracket. When you look at your pump assembly you will see that there is one bolt that has a nut on the back side......leave that one on as its not affecting removal of the pump.

Wally

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Now that you have done all that the pump will slide right out and this is what you have

Wally

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this is the bolt with the nut on the back side........screwdriver pointing to it. Make note of this cause it will serve a purpose later. (pic#1)


ok so we take that last bolt out and pull the houseing off. Look at the way the impellor turns and make note of it. Its actually marked on the back side of the pump housing but just to be safe incase you happen to have a reverse rotaton pump. As we can see in this pic there are 4 blades damaged that we can see even before pulling the impeller out.......its gets better....... (pic #2)

Wally

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ok we romeve the impeller to find.........holy cow!!! nothing left!!! (pic #1)


And this is where the whole back flushing this takes place.......luckly for us we didnt need to do this since all of the pisces were in the lower hose when i removed it!!! If they werent there you need to find them! Last thing you need is a piece going through the cooling system and cloging an exhaust cooling port! Most time what you would need to do is unhook the supply line going into the thermostat from the seawater pump and hook up the garden hose to backflush the parts out. (pic #2)

Wally

iTrader: (1)

now back to the pump drive itself. Theres is a stainless plate that sits ontop of it......remove it as there is a new on in the kit. And under that plate there will be an O-ring in the groove of the pump body. The screwdiver is pointing to it. remove the O-ring and disguard...

Wally

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And heres our rebuild kit. New impeller, houseing, bolts and O-ring, and new stainless plate

Wally

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now we begin to put it all back together....first the O-ring gets put back in the groove. Although its not needed i usually put a very light coating of grease on the O-ring and then install the stainless plate. I dont think there is a right or wrong way to install it but i have noticed that there is a sharp edge and a dull rounded edge on the plate. Most of the factory pumps have the sharp edge against the plate so that the way i usually put it back

Wally

iTrader: (1)

now comes the fun part of installing the impeller......its helps to coat the houseing and impeller with some liquid soap (Ivory is good since its 99% pure and wont polute the water) i didnt have any available so i used grease again. This does two things.....first it helps with the install and second it helps the impeller life on that first startup so its not completely dry. Make sure to install the impeller in the right direction!!! A twisting motion while pushing in helps.....did you remember to make note of it before? I have been told by different people that it doesnt matter which way you install the impellor....that it will flip over and correct itself on first start.......i dont feel comfortable about doing it that way and just install it the direction it needs to be in the first place
Oh and heres where oneof the zip ties will come in handy....you can zip the impellor up tight to help you install it