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Mercruiser 50 seawater pump removal

cliff_mygatt

New member
I have a 2006 5.0 MPI with a c

I have a 2006 5.0 MPI with a closed cooling system and B-3 outdrive in a Bayliner 265 SB. I have had a Guardian system alarm and have isolated the alarm to sea water pressure based on disconnection the sensor and the alarm going away. I have 191 hours on the engine and suspect the seawater pump needs an overhaul. The seawater pump is below the fuel pump and that is below the exhaust riser. Very tight spot. I would appreciate some advice for getting the pump out so I can overhaul it myself. The local Maintenance guys are suggesting pulling the engine would be the easiest way at $95 per hour for 10 hours of work (ouch). Any suggestiong would be helpful. I am planning of working it this coming weekend.
 
"[b]"I would appreciate so

""I would appreciate some advice for getting the pump out so I can overhaul it myself."

Ayuh,...
You've got to Remove however much of the Boat as necessary to get To it....
Sometimes that means Pulling the motor..."
 
"Unfortunately many boats &#40

"Unfortunately many boats (and cars) are built with low (or even reasonable) maintenace cost as a distant 12th on a list of top 10 design goals. For example, the labor cost the replacement of the T'stat on my wife's V6 Saturn wagon is quoted at over $300. You can't even SEE the T'stat housing when you pop the hood.

As Bondo says...whatever it takes...perhaps removing the exhaust riser or whatever will give you enough room. I know I'm not looking forward to replacing the impeller on my raw water pump on my FWC 5.7L MIE."
 
"Thanks, I appreciate your tho

"Thanks, I appreciate your thoughts. Just wondering if there is some secret out there to make it easier. Better than ponying up $1000, I think to do it myself."
 
"If you are reasonably handy w

"If you are reasonably handy with tools and have a good work ethic, most of the repairs on a boat can be done by you. Sites like this can offer a lot of help either directly or as a "go to...".

BTW... your test as described in the intial post is not definative... it could also be a bad (or plugged up) sensor... unless the engine is also overheating!"
 
"Agree, the test is not defini

"Agree, the test is not definitive. The local mechanic indicated and the technical manual agrees that the seawater pump should be overhauled about every 3 years. I keep the boat in the water year round. So, I thought I would overhaul as a precaustion as well as check the sensor. Thanks for your comments, this site has been very helpful."
 
"Both the manual and the mecha

"Both the manual and the mechanic are correct on the pump redo... especially if you don't have a good raw water strainer and/or boat in waters where you suck up sand and/or mud into your engine (a common problem where I am). On some boats that I've owned where you can replace the water pump impeller without even getting your hands dirty, I've replaced them annualy, keeping the removed one (if in good shape) as a spare."
 
"I do not have a strainer, whi

"I do not have a strainer, which seems odd but such is the case. I am not looking forward to getting this pump out of the boat but I am determined to do it. It will just take some creative thinking to minimize the removal of other components. I am quite handy mechanically, thanks to the Navy."
 
"Hi Cliff,

There is an easy


"Hi Cliff,

There is an easy way. Take the pulley off the pump, remove the 3 mounting nuts (1/2" if I remember correctly), then push the pump towards the rear of the boat until the pump mounting studs clear the mounting bracket, and then the pump should fall into the bottom of the boat. There is a slot cut in the bottom of the bracket you can't see while the pump is in place. Once the pump is in the bilge, you can usually get the hoses off but if not, disconnect them from the other ends and then pull the whole lot out from under the crank shaft pulley."
 
"I thought I might take the mo

"I thought I might take the mounting bracket off, 2 bolts and then swing the pump out to get the hoses off. I appreciate your thoughts. It is REALLY hard to get to. I can just see the pump and blindly get my hands on the pump. It will be a good weekend project for sure. Thanks for your thoughts."
 
Chris...
Thanks for the tip..


Chris...
Thanks for the tip... I'm coming up on season #4 with my new engine and have been dreading swapping the impeller.
 
"I managed to get the seawater

"I managed to get the seawater pump impellar replaced. 5 hours plus but worth it. However, the guardian alarm is still present. When I disconnect the pressure sensor, it goes away. So, I have ordered a new pressure sensor. Here is the rub though, when I run the engine RPM up in "neutral" the alarm does not sound. However, when I run the engine loaded, I get the guardian alarm around 1100 RPM. Again, when I disconnect the seawater pressure alarm, the locked in guardian alarm goes away and I get the 2 beeps every minute indicating the sensor is disconnected. I hope the sensor solves the problem but the shop I ordered the new sensor from has NEVER ordered one before. More to follow and I would appreciate your thoughts."
 
"Well, I replaced the seawater

"Well, I replaced the seawater pressure sensor ($114) on the power steering cooler and the Guardian alarm went away. It is great to have the boat back and running properly. I did not find any reference to the pressor sensor being a problem so I guess it is an isolated case. Anyway, good to have the problem solved. Thanks for your help and happy boating."
 
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