I know it's been said before, but check your impeller!

fi.na.tine · **Posted:** Sun Apr 12, 2015 4:27 pm

I want to first start by saying thank you to everyone here - you have given me the confidence to tackle some projects I have not been very comfortable with...

Such as changing my own impeller. I pulled this one out just now. Can't find the broken fins in my lines so they must be long gone. 1 fin is completely ripped off, another 1/2 way gone, and the 3rd is on it's way to being torn off.

A very simple job on my VP. On my friends Merc we'll have to tear apart the whole outdrive.

deafwish · **Posted:** Sun Apr 12, 2015 9:35 pm

Nice work!
How old was the impeller?

JohnScott · **Posted:** Mon Apr 13, 2015 7:37 am

It would be wise to try to find the broken off pieces as they may restrict flow or get stuck in thermostat/etc.. I replace impellers every two years regardless of condition. Best wishes.

babbot1 · **Joined:** Tue Mar 12, 2013 3:46 pm **Posts:** 570

This is on my short list before launch. The marina did it 2 years ago when I bought it. I only done my small outboard in the past. Did you have instructions somewhere or a manual? I know sometimes there are subtle tricks you only learn from the book or messing up and doing it again. I prefer not to mess this up.
I watched a couple YouTube vid's but they are back yard mechanics and not always trustworthy on the correct way.

ric · **Posted:** Mon Apr 13, 2015 9:04 am

Every 100hrs or 2 years with volvo whatever comes first, it's easy to do even while on the water. I changed mine yearly when I owned volvo, they're quite famous for falling apart and a $40 impeller is cheap.

Mercruiser Alpha 1 gen 2? Every 5 years or 200 hours whatever comes first. Some will argue longer they don't fall apart just get stiff. Give it to your mechanic it's a PITA but not expensive just one hour of labor.

LouC · **Posted:** Mon Apr 13, 2015 9:09 am

Did you look in the thermostat housing?

fi.na.tine · **Posted:** Mon Apr 13, 2015 6:01 pm

I do not know how old it is. it is original VP so it may be from 2008

- I looked all through the lines and in the thermostat. no signs of it. It looks as though it fell off in chunks, so they may have gotten flushed through.

As far as a guide, well - I am a backyard (Well, it's actually in my garage) mechanic, but I can give you the run down.

1) locate the pump. It should be on the lower left side, along the belt. It's got 2 hoses running into it and two large hoses going into it.
2) disconnect these hoses. Just d/c the hose clamps and wiggle the hoses off - look for cracks or wear.
3) there is a Mount on the right side - mine was like a bent rod that connected the pump to the engine. Remove the two bolts holding it on, then maneuver it off the pump.
4) There are 4 slotted screws on the face of the pump. Back these out and separate them from where they connect.
5) pull off the face - you may need to do some slight prying - I used a screwdriver as mine was painted together.
6) Now you can see the impeller, pry it out with two screwdrivers.

Replacement I can only imagine is the reverse. Why do I say it that way? Well the impeller West Marine provided for me is not the correct one. The OEM part number is 3584350 - of which I am guessing was renamed sometime since 2008. So right now I am trying to located the right part number and where I can get it from. I have gotten part #s of 18-3306 or 09-812B for a Jabsco replacement or 09-812B-1 for Johnson that look promising, but waiting for some type of confirmation.

I also changed my own oil too - something I have not done since I owned my first car in 1991. (The little things I know - but all of my cars have been worth it to just hand off due to me not having good contortionists skills or the hand size of a 4 year old.)

Once I get all the part #s and the right part I will take pictures. Trust me - it is not hard.

Go Stars · **Joined:** Tue Sep 24, 2013 8:14 pm **Posts:** 11

Bare with me as I'm still relatively new to boating, but why don't they make the impellers out of brass or something that doesn't break down as easily?

LouC · **Posted:** Mon Apr 13, 2015 7:05 pm

A raw water impeller has to be able to create hydrostatic pressure to move enough water into the engine all the way from the lower unit. It's totally different from a metal impeller in the front water pump on the front of the engine. So it has to flex..

babbot1 · **Joined:** Tue Mar 12, 2013 3:46 pm **Posts:** 570

fi.na.tine wrote:

I do not know how old it is. it is original VP so it may be from 2008

- I looked all through the lines and in the thermostat. no signs of it. It looks as though it fell off in chunks, so they may have gotten flushed through.

As far as a guide, well - I am a backyard (Well, it's actually in my garage) mechanic, but I can give you the run down.

1) locate the pump. It should be on the lower left side, along the belt. It's got 2 hoses running into it and two large hoses going into it.
2) disconnect these hoses. Just d/c the hose clamps and wiggle the hoses off - look for cracks or wear.
3) there is a Mount on the right side - mine was like a bent rod that connected the pump to the engine. Remove the two bolts holding it on, then maneuver it off the pump.
4) There are 4 slotted screws on the face of the pump. Back these out and separate them from where they connect.
5) pull off the face - you may need to do some slight prying - I used a screwdriver as mine was painted together.
6) Now you can see the impeller, pry it out with two screwdrivers.

Replacement I can only imagine is the reverse. Why do I say it that way? Well the impeller West Marine provided for me is not the correct one. The OEM part number is 3584350 - of which I am guessing was renamed sometime since 2008. So right now I am trying to located the right part number and where I can get it from. I have gotten part #s of 18-3306 or 09-812B for a Jabsco replacement or 09-812B-1 for Johnson that look promising, but waiting for some type of confirmation.

I also changed my own oil too - something I have not done since I owned my first car in 1991. (The little things I know - but all of my cars have been worth it to just hand off due to me not having good contortionists skills or the hand size of a 4 year old.)

Once I get all the part #s and the right part I will take pictures. Trust me - it is not hard.

Thanks for the rundown. I am going to take a stab at it this weekend. Putting the impeller back is where I want to make sure I do the correct thing. I know you have to use the special grease that comes with the kit and make sure the veins go back in the same direction so they don't have to force themselves back. Any gasket sealer?

rpengr · **Posted:** Tue Apr 14, 2015 8:57 am

Just thought I would put a Link here:
http://www.smwebhead.com/phpBB3/viewtopic.php?f=11&t=12060&hilit=rebuild
This post is where I rebuilt my raw water pump including replacing a bad bearing and seal. Has some photos of the water pump and impeller. This VP pump was the type mounted to the front of the engine crank shaft. The OP's pump was mounted in a belt driven position. Not much difference either way, but the belt driven is easier to get to.

For the Newbs, let me just say that it is not normal to need to replace the bearing or seal. Just replace the Impeller every 1-2 years. The seal is good for maybe 10+ years, but since it is fairly easy (and cheap) to change, some of us are considering changing the seal every 5-7 years for preventative maintenance. The bearing should only go bad if the seal went bad and kept getting the bearing wet.

Ray

fi.na.tine · **Posted:** Tue Apr 14, 2015 1:21 pm

Everything I have read says that the "Special Grease" Is Glycerine. Hand soap. It's just to get it in there, it does nothing once water runs through and flushes it out. (If I am incorrect, let me know as this was my next question after I find the silly thing....)

rpengr · **Posted:** Tue Apr 14, 2015 3:02 pm

fi.na.tine wrote:

Everything I have read says that the "Special Grease" Is Glycerine. Hand soap. It's just to get it in there, it does nothing once water runs through and flushes it out. (If I am incorrect, let me know as this was my next question after I find the silly thing....)

The special Grease is Glycerin - True. (more like AstroGlide than hand soap)

The purpose is so that friction does not melt the impeller to the brass housing while it is completely dry. Once the pump is primed, there will always be at least a little water trapped in it even after extended periods of not running (or freezing).

I would say that if you have your raw water pump apart, and don't have the glycerin, you could just pre-fill the hose from the pump to the thermostat housing with some water. That would prevent damage while the pump primes again.

fi.na.tine · **Posted:** Tue Apr 14, 2015 3:37 pm

or just put a couple of pumps of hand soap in there (Nothing alcohol or petroleum based) to do the same. I would think you would have to prime all your lines, otherwise that little bit of water in the pumps getting pushed right out and then it's dry for a brief period afterwards - but either would/should work....

deafwish · **Posted:** Tue Apr 14, 2015 4:19 pm

Having being stuck on a mate's wake boat in the middle of nowhere, his impeller fried from forgetting to open a seacock. :roll:

We replaced his & used sunscreen to lube it up.

www.iFourWinns.com

I know it's been said before, but check your impeller!

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