Brass Housings - Water Pumps - Impeller

[skolbe]

Okay tackling the impellers this week and have a friend helping me out. So, I spoke with three parts departments and they all spoke about how sand tears up the brass housings and they recommend replacing them at the same time. We will tear them down this week and see what we have but - have others seen grooves in their housings? I don't beach the boat and I really am careful in shallow water. Just curious what others have seen. Thanks in advance. My generator pump did not have any grooves that I could see. I could see after 10 years how the housings could go bad. Curious what others experience has been.

 

[skolbe]

Talked to the guy at the parts counter and he said Bravo - III's are really bad about stirring up sand and getting sand in the impeller housing and tearing up - said not as bad with Inboards.

 

[tbirdvet]

Just inspect housing when you have it a part. The parts guy may be just trying to make some extra bucks. Your housing is much more durable then the older plastic housings.

 

[Dave S]

I haven't seen that on my 350 mag. I now have 350 hours on her and she still holds about 10 PSI at cruising speed. What kind of water pressure do your engines maintain?

I have only changed my impeller once at about 200 hours and the only notable groove at that time was the one that is worn in the rear of the housing (this has been discussed in a previous topic and apparently Merc has some stainless shims to fix this). Our water has a lot of sand in it because our lake is part of the Catawba River basin and anytime we have a great deal of rain it can turn muddy from water runoff. Plus our marina is very shallow and almost every time I dock my boat I stir up the bottom and I know this muddy water gets sucked into the water intake and thru the pump.

Replacing those pumps is not exactly cheap either especially when you have two of them like you do.

Dave

 

[skolbe]

That makes me feel better. I just hated to drop a boat buck replacing housings - the parts guy - must have sucker in my profile. Just kidding.

 

[Ididntdoit]

Mine are scored pretty bad - next impeller change I will probably mill the end plate but I will not replace the housings as I get plenty of pressure - I converted my B III boat to seacocks/strainers for the reason mentioned above (among others, read on) When I had a problem with the port engine getting low water pressure last year merc wanted me to replace the pump (at my cost even though I had the extended warranty) to prove to them it was not the problem I swapped the one from the starbord side (which was getting plenty of pressure) and STILL LOW PRESSURE - I later asked if I had popped for the new pump ($350) would they have re-imbursed me - the answer was NO - BTW it ended up being a blocked hose between the outdrive and bellhousing, just like I told them it probably was in the first place (thanks to CSR) Another reason I converted - somthing just doesn't sit right with me about not being able to "shut the water off"

 

[Escapade]

Scott-
Our boat came from previous owner in sandy Michigan. At impeller change we did noticed scoring. Pressure looked good but, it is obvious this would adversely affected the impeller life. I did buy new pumps and plan to change them over in a few weeks. The cost was about $200 each.

 

[skolbe]

Well - I guess I will see when they come part. Thanks for the updates.