Sea Pump/Impeller question
 

So, I decided to check for leaks and loose fittings and lines before splashing the boat this weekend, at some point the muffs slid off the outdrive and the impeller in the sea water pump ran dry, I think it was only a matter of seconds, so, I am sure the motor is fine [closed loop cooling] but, I pulled the lines off the sea pump and checked them for restrictions or debris and they seem fine, also, when I run water "backwards" through the suction hose, water pours out the outdrive, so, I am pretty much positive I smoked the impeller in the sea water pump? I have been told by a few people that it doesn't take long when you run these things dry to chew up the impeller.

I have looked at the pump and its pretty easy to get to, its in a 24ft Outlaw, so, I can get to it from "up top"

Can I just spin the 4 bolts out of the back of the pump and change the impeller with the sea pump in the boat? or do I have to take the entire pump off to change it?, if I can leave the pump bolted up, do I have to loosen off the belt?, or does the input shaft for the impeller run straight through?

It looks like a pretty simple fix, but, figured I would ask here first, BEFORE getting into anythng over my head. I have been pricing the impeller rebuild kits and they aren't real expensive, but, there is a big difference in price from place to place, anyone know the cheapest place to buy them?, or have one lying around?

THANKS! again for ANY/ALL input!!

Michael

If it only was a few seconds ,,i think u be fine .

Just check if the pump is sucking the water from the muff's in and u can tell if the impeller is bad or not !!

I just did this on my twin small blocks in my Sonic 28. I pulled the belt off, took the whole pump out and replaced both gaskets and a wear plate that came with the kit. There is no way you can put the impellar in with the pump in the boat. Take the extra time and pull the pump and do it right. You will thank yourself later. Its a pretty straight forward job. best of luck.

I just did one of mine last week. You can prob do it with the pump still installed, however it's easy to get it off and it makes it a much easier rebuild when you can set it on a bench and see what you are working on. It is a very simple repair. FYI. Be sure that you know the direction of the motor before you squeeze the impeller in.

we just pulled the housing off the back of the pumps on ours. took us longer but the pully was safety wired so i didnt want to mess w/ it. next yr i am cutting the wire & goin in from the front.

shouldn't you be replacing the impeller's every year anyway? I have noticed the impeller blades that are pressed against the housing take a set over long periods of not running and then the blades fracture or break off when the pump is once again turned!

I had an engine builder put a flow meter on the impeller and it was fine, at least it was til I ran it BONE dry!

I did try to hook the muffs back up and fire the boat, ran for about 2 seconds and no water out the exhaust, so, I am pretty sure its toast, there was also little chunks of rubber in the line, so, that CAN'T be good.

Sounds to me like it would be easier to just yank the whole pump off and put the impeller in on the "bench"? I assume I should check and see which way the "fins" have to face before putting it back in?, its a single 454 with the sea water pump on the same side as the helm, if anyone happens to know off the top of there head?

Also, would anyone have a part number from Mercury for the rebuilt kit?, problem being, the boat is at my cottage 2 hours away, and, obviously, so is the impeller, and all the marina's around here want me to bring it in so they can "match it up", so, a part number I can use to order one would be GREATLY appreciated!!

Thanks!
Michael

Is it a stock Mercury water pump? Also plastic pump housing?

You will find what you need here!

www.cpperformance.com

I would get you a link to the exact page but their website appears to be down :angry-smiley-038:

I do my Donzi with the pump in the boat and the Formula I take the pump off because it has offshore motor mounts. It can vary from boat to boat the best way. I ran a pump for about a min with no water and took it apart to find out that it was fine. It depends on if there is any water in there when you are running it and at what RPM. It will take a LOT longer then 2 seconds for you to get water out the exhaust even with closed cooling. I would with out a doubt check the thing, it is easy and the piece of mind out weighs the worrying about it tell you do. I replace my water pumps on even years so I did them last year and will do them next. It is easy for me to keep track that way.

Yes, its a stock Merc pump, serial number on top of motor has "yellowed" and I cant read it, which sucks, since that seems to be what is used to reference a lot of parts!

My pump is the plastic style with the "1 piece" rear housing, looks pretty easy to change, might have a crack at doing it myself, IF I can find the impeller kit somewhere reasonable, if not, well, its back to "Bullet Engines" who, by the way, have treated me, VERY, VERY well!

THANKS AGAIN! for all the help guys!

Their should be a tag pop riveted to the block right above the starter with the serial number you will need a light too see it. By the way if you saw rubber parts then the impeller is bad. And if it's a bravo 1 drive then make sure you are covering the low water pick up holes also, And you should look in to buying a set of new muffs from merc that has a long rod that goes thur the holes on the lower unit and will push and lock on up against the drive so it will not slip off. The fastest way to know if you think you impeller is going out is to carfully put your hand on the out side of the impeller housing to see if it is hot or cold while running, If it is hot then it is bad. And also you do need to run the engine out longer then 2 second But no longer then 45 seconds to wait to see if water comes out. Good luck with it.

What year is it and what drive?

When you figure out the right impeller, and you've got the pump out, do be sure to remove all the debris. Like you mentioned, you saw chunks of rubber. Well, those chucks of rubber tend to get caught up in the hoses and block the flow of water. You might get lucky, but you might not. I had it happen once where I put in a new impeller and the next time in the water, it slowly over heated. Turns out there was chucks of rubber blocking the flow. Removed the hoses, shook out all the rubber, put it back together and never had another problem.

Not sure what year boat you have - but it's always easier to remove the pump assy to change the impeller/housing. If your sea water pump has the lift fuel pump on it - this would also be a good time to change/check the gear oil in it as well.....

Great! will do, thanks for the tip on the "pop riveted" serial number, will make things A LOT easier if I have that! I am running a 95 454EFI with a Bravo 1 drive, which holes are the low water pickups?, I just put the muffs over the "gills" on the side of the outdrive, are there other areas that need a water supply? this would be much easier if I had room to install a sea strainer!

I have flushed water "backwards" through the suction side of the hose, but, how hard is it to actually remove both the sea water hoses? [at the outdrive and wherever the pressure side connects] I like the idea of checking to see if there is any small rubber pieces stuck in there, I really dont want to have to tear all this stuff out again in a week or 2 to get the rubber pieces out.

THANKS!!!

My boat is a 95, I am about 2 hours away from it now, but, from what I can see/remember it takes the impeller that fits inside a "1 piece rear housing", not the newer style, or the very old style with multiple "plates" for a rear housing, just need to verify and get a part number and may have a crack at doing it myself, THANKS!

You can remove the suction hose from the pump, and flush water from the drive, through your muffs to clean out that hose. Or you can easily remove that hose at the gimball ring. Look for it at the lower side of the gimball ring. A little tought to find, but sholdn't be too tough to remove. If I remember it comes out the port side, and the pump is on the starboard side. The other hose, from the sea pump to the water pump should be removed and shook out. Also, remove any smaller hoses that are easy to get to ... from the pump to the water neck... from the water neck to the exhaust... anything else i'm not thinking of. The smaller hoses will capture the rubber easily. They're simple hose clamps, and only take a minute to remove and clean out.

The 1 piece body and 2 piece body use the same impeller.Impeller is #89740.One piece body only has 1 wear plate #94576.One piece body uses a o-ring seal between the body and wear plate #25-33465. You can get all these at ishopboating.com.

THANK YOU!!!!!!!!

I have been rippin' whats left of my hair out trying to locate the part numbers from the Baja/Fountain site, the Mercury site, numerous marina's, man, you would think it would be pretty easy to find this stuff???

I hate to ask, but, is there a part number for a "kit"?, or do I have to order everything individually?, THANKS AGAIN!

Michael

I actually found an impeller "kit", the part number [Mercury] is 47-59362T-7

Any idea if this will work?, I THINK its the right one, but, dont want to get it all apart and find out its not correct, Thanks!

YEP !!!!!! it will work.

Thanks, thats great, at least now I can get started, THANKS A LOT guys!

Because you have a 1995 set up your boat dose NOT have the low water pick up I was talking about, So you should be ok. If I remember right they started the low water pick up thing around 1998ish.:party-smiley-004:

I would call Dana at Doller Marine. She can listen for a few minutes of "thingy majigs" and the "blue part next to the black part" and after a few days the right part will come in the mail.

A FEW more questions below, I am pretty much ready to start spinnnin' wrenches, thanks guys!

OK, I picked up a rebuild kit today, came with a new plastic housing, hardware, wear plate and a small O ring

Seems easy enough, but, I was wondering where does the small O ring go?, there is already one pressed into the plastic housing, and there is no reciever groove in the wear plate, so, where does the small O ring go?, I assume is seals the shaft up somehow, but, not sure how.

Also, do I have to use sealant on the threads and/or housing or wear plate when I reassemble the unit?, Thanks for all the help guys, I was a little hesitant to try this, but, after getting some good input from OSO members I am not quite so intimidated now, Thanks Guys!

Michael

According to the diagram I looked at it goes on the shaft first,then the wear plate,then the impeller and finally the body.No sealant is needed but you may want to put something like vaseline or white grease in the pump body to lube the impeller on start up.Does that o-ring actually have square sides on it? It's known as a quad ring.

Two things....

1. Make certain it is an actual Mercury part and NOT Sierra branded. Had troubles with Sierra's in the past.

2. Do NOT, use vaseline, white grease or any type of grease for that matter. The little globules of grease dont dissolve and can find their way to some small orifice and clog it up. Use dishwashing liquid; dissolves in water completely.

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Don't tighten up the bolts too tight on the plastic housings. They will crack and you will have to buy another one. I also grease the inside of all my hoses for easy removal.

Hey Guys

Thanks! again!

The small O ring appears to be round, but, I haven't opened up the package yet?, makes sense it goes on the shaft "first" will give it a shot and see what happens and let you guys know, be nice to actually INPUT some information for a change! ha ha!

Great tip about dish soap!, it works well as a lubricant and its cheap, not only does it break down in water, but, in the HIGHLY LIKELY scenerio that I spill 1/2 quart of it all over myself it wont ruin my clothes and its easy to clean up, pretty much a "win/win"!

Is there an actual torque rating for the bolts?, I do have 3/8 and 1/4 torque wrenches I can use to torque it, most of the stuff I do I use the "JBS" torque scale [Just Before Snappin'!!]

Thanks again, guys!

Michael

The best tourge is to STOP befor your JBS !!!!:grinser010:

Just hand thight and then a little more !!

You don't need to worry about orienting the impeller vanes in relation to the pump rotation. The housing is ovate which allows the pump to pump. There is a high pressure side (more constricted) and a low pressure side (less constricted). Water is sucked into the low pressure side and hurled out of the high pressure side. As the impeller spins it's first few revolutions, all of the vanes will orient themselves in the correct direction (or maybe deflection is a better word). So, just lube it up and stuff it in there!!!

Thirdbird, Are you SURE?, man, that would make the install A LOT easier, but, really dont want to not orient the impeller blades and end up smoking [another] impeller, I looked at the housing [its just a plastic piece with 2 inlets that both look identical] and it appears to be round? maybe we are thinking of 2 different seawater pumps/housings?

Let me know, Thanks!
Michael

Like i said before ,,they will straighten themselves out !!!

I was out at my shop today and thought about your pump.I had one in pieces on the shelf so I got it down.It was the 2 piece body style so I put it together with the impeller vanes in the wrong direction.I left the end off so I could watch the impeller.Lubricated it with oil and then turned it over by hand and it went right into the correct direction in one revolution.What ThirdBird was talking about being oval is where the impeller runs inside the pump body.As the vanes pass the larger end of the oval they flip right in place.However it's no big deal to assemble them in the correct direction.Also looked on the bearing housing part of the pump and it has a grove in it for that small o-ring or quad-ring going around the shaft.Leave the bracket on the pump when you take it off the engine so you don't accidently put it back on upside down and hook the hoses up wrong.

West Marine has the impellers, $30 bucks, page 432 of the 2009 Catalog or search West Marine on line. Use dish soap to lube it up when you install the impeller in the housing, slides right in and saves it untill the water gets there on first start up. Do it once a year and boat with no worries.

[QUOTE=n20michael;2874898]Thirdbird, Are you SURE?, /QUOTE]


Yup!:cool: