Replacing raw water pump impeller on '96 Mercruiser 350 EFI with Bravo One

[Rogerdog23]

Looked in the archives and haven't seen this covered for my engine...so hopefully this isn't a repeat.

​Motor serial number: 0L012308

I started hearing a squeaking noise last season and finally pinpointed it to the raw water pump. I was able to do so by spraying WD-40 behind the pulley on the pump and the noise would go away for a minute or so. I've also run the engine for 5+ seasons and haven't replaced the impeller so figured I'm way overdue after reading a number of posts here (and it sounds like that can cause squeaking as well).

My questions are as follows:
1. Is there a link somewhere to the steps on how to replace the impeller and I'm guessing the two ball bearings the shaft sits on (to get rid of the squeak)?
2. What is the level of difficulty for this job? I'm pretty handy but haven't done this before.
3. Any thoughts on a parts list? Impeller rebuild kit, the bearings (2), and what else? (could do everything other than the shaft and metal housing). Sierra okay or go with OEM?

Appreciate any thoughts!

 

[tpenfield]

You can go to the mercruiser part web site to get some illustrations on the sea water pump and other components of your engine. You would want to get (download) the service manual for your engine as that will go through the water pump disassembly/repair.

Also, check the prices of a new pump . . . it may be the better way to go, if you do not have the right tools to disassemble and install the bearings in the housing.

 

[Rogerdog23]

Thanks. I found a friend who has the manual and it does look like buying a new pump might be the way to go. Any thoughts on the need to stay with an OEM pump (about 480 bucks from the mechanic) vs an aftermarket pump that is cheaper? I see Performance Product Technologies (PPT) sells a brass replacement pump with pulley for 345 bucks, and other options on eBay. Not sure if someone has tried aftermarket and had a great experience with it?

 

[Mischief Managed]

I would check the bearings before you drop a few hundred on a new pump, they should last a REALLY long time and don't typically squeak when they fail. The squeak might just be the belt. A new belt and new impeller kit are a lot less money than a new pump. Pull the pump, remove the impeller and see if the bearings operate smoothly and without much end play on the shaft.

 

[alldodge]

Agree, check the bearings first.
There is a link in my sig for rebuilding the pump and parts needed. Mine is for a carb mounted model, yours is the same so far as parts, and you would use grease.

Five years on one impeller, your pushing your luck

 

[Rogerdog23]

Helpful, will give it a try. Sierra okay for the rebuild kit? How often should I change the impeller moving forward (30-40 hours per season on the engine). Appreciate everyone's help and thoughts--will let you know how it goes.

 

[alldodge]

Impellers every two years is what I recommend for the belt driven pump.

 

[thumpar]

I do every 2 years on mine. Pull the pump out and see what you have before ordering a new one. I use the one with the plastic housing to make it easier. If I was going to go to metal I would get the Hardin Marine stainless housing. It is one piece like the plastic one.

 

[tpenfield]

I do 3 years . . . but I run sea water strainers, which help with longevity. I just replaced the impellers on the 'twins' this year. The 3 year old impellers were in good shape, but you could tell that they were getting brittle.