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"Sea Water Pickup Pump" - Disassemble and inspect: "Whenever insufficient seawater flow is suspected. (if operating temperature exceeds normal range)

I change mine every other year just to be safe.

I change mine every 2 years "Just in case".

EVERY 300 HOURS OF USE OR THREE YEARS
• Replace water pump impeller (more often if overheating occurs or
reduced water pressure is noted).1...........
.......
1. These items should be serviced by an authorized dealer.

I save my old one if not torn up as a spare - in case I have one that fails - could save a day. I would make sure you trailer when replacing. Not sure but I bet water would start flowing if hose was pulled off. any one know for sure?

Not sure but I bet water would start flowing if hose was pulled off. any one know for sure?

Mike,

Basically the bracket is cut i half. I used to find it very difficult to replace the 2 bolts that secure it to the block.

The two halves of the bracket are now held together by another 1/4" thick bar, permanently fixed to the piece that is engine mounted. This is dowelled ( M6 bolts with the heads cut off ) and has 2 M8 studs, so the other piece which locates onto the pump is easily removed / replaced using 2 locknuts. Easily visible and accesible.

Graham

Author:	07H200SS [ Mon Feb 23, 2009 10:04 pm ]
Post subject:	Impeller?
Read some recent posts about this, but curious for those who have changed theres how bad did they really look? I have 115 hrs and have everything else maintenance wise done for the upcoming season. Should I consider doing the impeller also?

Author:	230 Mike [ Mon Feb 23, 2009 10:24 pm ]
Post subject:	Re: Impeller?
Lots of people have waited 5-6 years to change it and been fine, but I wouldn't recommend going more than 2. The risk of having it come apart due to debris, water conditions, or even a flaw in the part aren't worth it. I changed mine last year at 3 years and it still looked new, but then I'm a driveway boater.

Author:	07H200SS [ Mon Feb 23, 2009 10:53 pm ]
Post subject:	Re: Impeller?
We bought our boat used and the previous owner used it mostly on the Mississippi River. The boat had a lot of sand and grit inside of it so I am assuming the river is pretty sandy. This is what makes me want to change it. Guess I might as well do it?

Author:	ht32bsx115 [ Mon Feb 23, 2009 11:28 pm ]
Post subject:	Re: Impeller?
My dad bought a 1966 Marktwain (150 Mercruiser) in 1966.... I was kid then and we had a lot of fun with that boat.. I brought it up here to the NW in 1997 and ran it in Lake Washington and it seemed to over heat at low RPM but was more or less ok 500 or more rpm above idle. I called my dad and asked him when the last time he changed the raw water pump...........He said raw water pump? (When I changed it there wasn't much left of it...) I am surprised that it pumped at any RPM!! He used to pound on the thermostat housing thinking it was stuck closed!! The pump lasted so long because he NEVER ran it dry I suppose.... My brother (who formerly owned my 211 Lib) Bought a new Ski Centurion in 2000. (Mercury 300hp 5.7MPI with Bravo raw water pump) He called me last Jul from the middle of the lake on his cell phone to ask me how to change the raw water pump.... That one went 8 years. Last summer I Helped a friend change his (94 Bayliner) Mercruiser 3.0L engine (after he allowed it to freeze the previous winter) He bought the boat used from a dealer. He had the boat for 10 years. I asked him when he changed the raw pump........ (Another deer-in-the-headlights look) "what's a raw water pump" That one went 10 years or so... My 1997 Mercury Marine Owners Manual indicates: Quote: "Sea Water Pickup Pump" - Disassemble and inspect: "Whenever insufficient seawater flow is suspected. (if operating temperature exceeds normal range) By that I guess I could run it until the temp alarm goes off! I guess what I'm saying is that you could let it go for quite a while but at some point "Murphy" will be riding with you and it will fail someplace bad. My brother had to change his in the middle of the lake with a crescent wrench and a pair of pliers water was spewing everywhere!!.....The raw water pump on a Bravo engine is like a Volvo.....on the engine and he had a spare (luckily)..... If you have a Mercruiser Alpha you're not so lucky. you have to drop the lower unit to replace it. Not hard to do (unless you're at the lake!!!) OMC Cobras aren't hard to change in the water......just don't drop the bolts or other parts..... Bottom line? have a look at it every few years or so. Since they're fairly cheep.....it's just prudent NOT to put the old one back in....carry a spare too maybe..... If you run it dry for more than a few short seconds, change it. (Sorry for the long post. My wife doesn't ask me what time it is anymore .....she knows how to build a clock now!!!) Cheers, Rick

Author:	Graham R [ Tue Feb 24, 2009 3:26 am ]
Post subject:	Re: Impeller?
I change mine every 2 years "Just in case". I now have 4 old impellors and O rings in the boat, all of which look perfect! Graham

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Author:	jsimon [ Tue Feb 24, 2009 5:43 am ]
Post subject:	Re: Impeller?
I bought our old boat (99 258) the last month of the boating season, we unsed it several times and then winterized it and put it away. found our current boat over the winter endend up selling the 99 to a guy I know and buying the 03. The next summer I get a phone call asking me if I ever had problems overheating. I reimnd him I only used the boat a couple of times before he bought it, he was stranded on the river with the engine overheated. Anyways he took it to the FW dealer and found the raw water pump imeller went on it. No big deal, didnt cost that much, except the inconvienence, but later the same year he had to put an engine it it, so I think it got hotter than he thought... I change mine every other year just to be safe.

Author:	ht32bsx115 [ Tue Feb 24, 2009 1:31 pm ]
Post subject:	Re: Impeller?
Quote: I change mine every other year just to be safe. Quote: I change mine every 2 years "Just in case". Here's what Mercury indicates now. @ http://www.mercurymarine.com/_media/pdf ... mation.pdf Quote: EVERY 300 HOURS OF USE OR THREE YEARS • Replace water pump impeller (more often if overheating occurs or reduced water pressure is noted).1........... ....... 1. These items should be serviced by an authorized dealer. Volvo Penta is similar. Changing it every 2 years (or every other year) is a pretty good idea. You should never have to worry about it. If you run it dry though, even for 30 sec.....change it.

Author:	scottmph [ Tue Feb 24, 2009 1:35 pm ]
Post subject:	Re: Impeller?
I save my old one if not torn up as a spare - in case I have one that fails - could save a day. I would make sure you trailer when replacing. Not sure but I bet water would start flowing if hose was pulled off. any one know for sure?

Author:	07H200SS [ Tue Feb 24, 2009 2:02 pm ]
Post subject:	Re: Impeller?
Just ordered a new one today and going to save the old one as a spare.

Author:	jsimon [ Tue Feb 24, 2009 2:38 pm ]
Post subject:	Re: Impeller?
waytooslow wrote: I save my old one if not torn up as a spare - in case I have one that fails - could save a day. I would make sure you trailer when replacing. Not sure but I bet water would start flowing if hose was pulled off. any one know for sure? The mechanic at the Four Winns shop I use tell me that you can change the impeller on a Volvo (not sure about Mercury) with the boat in the water, he said take the hose of the pump and put it behind the pump and it pinches the hose off so no water comes in. I have never done it myself.

Author:	Graham R [ Tue Feb 24, 2009 2:59 pm ]
Post subject:	Re: Impeller?
I must admit that when I change the impellor on mine (on land) I leave the hoses on the pump housing. In my on-board tool kit I have some self locking pliers (Vise grips) which I'd use to shut off the inlet hose, should I have to do an impellor change whilst out at sea. I reckon I could do a change very quickly; due to the M5 Allen cap head screws I have substituted for the original brass screws, plus the modified (2 piece) retaining bracket. Graham.

Author:	230 Mike [ Tue Feb 24, 2009 3:48 pm ]
Post subject:	Re: Impeller?
Hey Graham, how about some details on that modified bracket?

Author:	ht32bsx115 [ Tue Feb 24, 2009 4:31 pm ]
Post subject:	Re: Impeller?
Quote: Not sure but I bet water would start flowing if hose was pulled off. any one know for sure? If you look at the back of your boat and notice where the resting waterline is(or you know approx where it is) and it's higher than the raw pump housing you will get water flow until you raise the raw water supply hose (when you disconnect it from the pump housing) above the waterline. When my brother did his he had to stuff a rag in the hose to prevent the water from running into the boat. The hose wasn't long enough to tie it up above the waterline. you could get yourself a cork or rubber stopper etc, and use that. In fact, make up a little tool kit for changing the pump on the water. Include the a spare impeller some suitable tools and a cork.

Author:	Graham R [ Tue Feb 24, 2009 4:54 pm ]
Post subject:	Re: Impeller?
Mike, Basically the bracket is cut i half. I used to find it very difficult to replace the 2 bolts that secure it to the block. The two halves of the bracket are now held together by another 1/4" thick bar, permanently fixed to the piece that is engine mounted. This is dowelled ( M6 bolts with the heads cut off ) and has 2 M8 studs, so the other piece which locates onto the pump is easily removed / replaced using 2 locknuts. Easily visible and accesible. Graham

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Author:	Jim_R [ Sat Feb 28, 2009 11:04 am ]
Post subject:	Re: Impeller?
Graham R wrote: Mike, Basically the bracket is cut i half. I used to find it very difficult to replace the 2 bolts that secure it to the block. The two halves of the bracket are now held together by another 1/4" thick bar, permanently fixed to the piece that is engine mounted. This is dowelled ( M6 bolts with the heads cut off ) and has 2 M8 studs, so the other piece which locates onto the pump is easily removed / replaced using 2 locknuts. Easily visible and accesible. Graham How about a picture? I'm having trouble visualizing this. Here's mine.