I'm due for an impellor change on my 350 MAG MPI and was wondering how much is involved? It's located within the water pump, correct? Do I need to remove the pump or is there an access plate/panel? Any advise and/or tips?

"My old man is a TV repairman, he's got this awesome set of tools. I can fix it." - Jeff Spicoli

 Greg

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2008 240LS - "Lee'Sure Time"

Let me start by saying that I have not done a merc yet, I've only done my Volvo so I'm basing my statement on that but they look very similer to service. The toughest part was getting the pump out. The hoseclamp screws were difficult to get to and it's tough to get much leverage down there. Once you have it out it's pretty simple. One suggestion is to note which direction the fins are bent in so you can position the new impeller in the same direction. I dont know if it would damage it but to me it seem to be hard on the impeller to have to repostion itself inside the housing. Also some suggest also put vasoline or grease around the inside of the housing to help with the dry start up that will occure after you're finished.

I was able to do mine on a Penta 5.7Gxi. The pump was located at the front bottom portion of the engine.  After removing the bracket that held the impeller housing in place (bolt), I loosened the 4 brass screws and gently pulled the housing back far enough to gain access to the impeller and O ring.  I did not remove my hoses.  Noted how it was installed removed it with some pliers and installed the new one (Volvo provides special lube with each impeller) installed the new O ring , 4 screws and hosing bracket.  Ran the engine an observed a good amount of water was coming out of the exhaust.  On a scale of complexity 1 out  5.

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05 270cr
"Scotch 'n' Water"

Life's a breeze when you live by the sea!

Greg, on a Merc, it'll be located on the lower left portion of the motor as you face it.  It's not too difficult.  Remove the bracket that holds the housing to the block and then hoses, release belt and get the unit out.  Then you can pop it open and replace the impeller.  Put some vaseline or something on it to help you spin it in noting the rotation of the old one. 

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O'
"Little Mascara 3"
266BR,496 MAG-Bravo III

Thanks for the replies

Mike, with the Merc, are there any gaskets or other parts that I'll need to replace while doing the impellor? Also, approximately how much is an impellor?

Greg

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2008 240LS - "Lee'Sure Time"

I did my impellor last spring. It can be a little awkward to get at, but it can be taken out.

On mine I fornd that my housing had some bad scratches, so I had to replace the whole pump. The newer ones are not rebuildable. Check yours for any grooves or wear in the brass housing. The worst part of putting my new pump in, was the pulley had to be pressed off the old one and put on the new one.  If you need a whole new pump, it will be 200+ dollars   Impellors are cheap.

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2005 202 LPX
6.2L Bravo 1

I've not done one of the newer brass housing units.  I can't see mine or reach it easily so I pay to have it done.  When I purchased the impeller before for the old plastic housing unit, it came with a new wear plate and all the gaskets. 

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O'
"Little Mascara 3"
266BR,496 MAG-Bravo III

I did one on a 350 mag last year, the only problem we had was the impeller housing was hitting the crank pulley. we had to remove the housing stud on the motor and cut it down. We used a long tie-wrap to collapse the impeller while you re-install it, it worked like a champ. Be sure to lube the impeller prior to installing. The impeller was around 20.00. The entire job took about 40 minutes.

 

 

 

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2000 248 BR, 7.4l, Bravo 3

"CRAP SHOOT"

Cincinnati, Ohio

Bob Otte:

I did one on a 350 mag last year...

Bob,

What year 350 MAG were you wrenching on? Mine's an '08.

Greg

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2008 240LS - "Lee'Sure Time"

I'm gonna head out to my carport later tonight to look at the engine/area a little closer. Thanks again guys and I'm sure I'll have some more questions.

Greg

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2008 240LS - "Lee'Sure Time"

almost positive it was a 2005, 240 ex

 

 

Bob

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2000 248 BR, 7.4l, Bravo 3

"CRAP SHOOT"

Cincinnati, Ohio

I finally dug a path to my carport through all this lovely white stuff on the ground that we got slammed with here in South East, PA

Any rate, I took a closer look in the engine compartment and took a couple of pictures of all the pulleys. I can see one for the alternator, one for the power steering, a couple of idler pulleys and two that are above each other centered on the block. The only one that's left that I believe is the water pump is at the bottom left (just above and slightly to the left of the bilge pump). Can anyone help me decipher this? If I'm correct about that being the pump, that location looks to be a real pain in the D to get at/work on...let me know. Thanks!

Greg

 

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2008 240LS - "Lee'Sure Time"

Greg, that is the one.  I am going to do mine in the spring.  I was just thumbing through the Merc manual today and it seems pretty easy.  I think that you should spray the bolts with WD-40 a few days before doing it to loosen them.  Take notice of how the fan belt is on so you can put it back the same way.  Good luck!  Let me know how long it takes.  Thanks,  Jerry

Just a couple days ago, I found out the hard way that you need to drain the water pump when winterizing the engine.  My impeller was frozen solid in the housing. I had planned on replacing the impeller(110 hours on the boat), but now I have to replace the plastic housing as well.  The water pump was easy to remove, but my rear seat is currently removed from the boat.  The bolts should be very easy to remove once you break them loose.  Getting the hoses off is the biggest challenge.  Here is the cheapest place I've found to buy the impeller and housing kit:  http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=390132152561&viewitem=&sspagename=STRK%3AMEWNX%3AIT

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2000 Crownline 202BR LPX
350 MAG MPI
Aerial Assault tower
Powertech 4 blade 17p SS prop
Aerial Double Bullet Tower Speakers
8 Polk Audio Speakers
2 MB Quart amps
1 Rockford Fosgate 10" sub

Greg Ball:

I finally dug a path to my carport through all this lovely white stuff on the ground that we got slammed with here in South East, PA

Any rate, I took a closer look in the engine compartment and took a couple of pictures of all the pulleys. I can see one for the alternator, one for the power steering, a couple of idler pulleys and two that are above each other centered on the block. The only one that's left that I believe is the water pump is at the bottom left (just above and slightly to the left of the bilge pump). Can anyone help me decipher this? If I'm correct about that being the pump, that location looks to be a real pain in the D to get at/work on...let me know. Thanks!

Greg

 

 

Greg, your's is an EASY one!  On the 496 crammed in a 266, imagine the floor going up almost to the edge of the belt.  Then, picture that seawater pump (water pump is still on the front of the engine-known as a recirculating pump on a marine block) down below that floor where you can't possibly see what you're doing.  Doh!

 It's really not hard with what you've got.  Loosen the belt tensioner, remove belt, take bracket holding the housing to the block loose, remove 2 hoses, pull assembly out, take apart, replace impeller in same orientation, inspect housing for severe wear, repeat process.  If your's is the plastic housing, make note of top and bottom hoses BEFORE removing them.  Once you remove the bracket holding it to the engine, it will rotate and can mess you up.  It did me my first time.  Just mark TOP on the top hose before you start. 

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O'
"Little Mascara 3"
266BR,496 MAG-Bravo III