Raw water pump - green salt corrosion?

[kable]

My wife and I picked up our first Catalina 34 this past fall.  Been having a fun winter dreaming and getting her ready for spring.

So the PO replaced the raw water impeller as part of her fall maintenance just before putting the boat on the market.  It isn't leaking, but doesn't look good and my thoughts are around preventative maint.  I assume saltwater, in the past(?), is causing this discoloration?

Attaching picture, hope this works, because I don't see it in the preview. 

Thanks,
Kable

[J_Sail]

To me that sure looks like the gasket has been seeping (i.e. a tiny bit of leakage) just enough to cause it to stay damp with corrosive seawater.  Let's see what some experienced owners say.

[Braxton]

I once had to replace my impeller in a non routine situation and ended up having to reuse my gasket.    (I'm now better at checking my inventory of small items like that).   With the old gasket I ended up getting a little bit of seeping and a tiny spray (more on that later) that caused corrosion and discoloration just like that.    It also didn't take long to happen.   By the end of the weeklong cruise there was already a significant amount.

I new gasket and a little bit of time cleaning it stabilized the situation.

It's hard to tell by looking at the picture but it seems you may have a buildup of salt crystals around the edge.    Are you sure it's still not leaking?

Once you are sure that the leak is fixed you need to make sure that you get the dried salt crystals cleaned up.  Salt is hydrophilic and will absorb moisture out of the air, so you will continue to have a corrosive solution there until you get all the salt cleaned up.

Also look around the rest of the engine compartment to make sure you don't have a buildup else where.   In my case I had a tiny little spray that would intermittently flick a drop of saltwater up over the top of the engine and down onto the fuel shutoff lever.   The salt I didn't find there the first time around eventually seized the lever causing a few anxious engine start or stop scenarios till I got it worked out.   The point of this long winded story is that salt water leaks are insidious, make sure you get everything cleaned up or it will tend to bite you later.

[KWKloeber]

Kable,

I agree that it looks like a continuing-to-leak paper gasket.  The PO may have reused rather replaced the paper gasket, or the cover may be a little warped, or.... who knows with POs.   

Pull the cover, clean all the surfaces completely, and replace the gasket (keep some spares also.)  You can make a gasket if you want to cheap out.

The new Ob pumps (N202 series) have a different flat cover, with a o-ring (instead of a gasket).  The groove for the o-ring is machined into the pump body, not the cover.  That works better than the fragile gasket.

Option-
Don Moyer has a cover that also incorporates an o-ring instead of a gasket (see attached photo.)  It's NOT THE SAME cover and size as fits the new N202 pumps -- this cover fits the original 202 (non "N") pumps, which is the pump you have installed.  An option to consider versus using the paper gaskets.
see Don's store:  http://www.moyermarine.com/catalog.htm
Search Keyword "370"
It's item CSOB_10_370

Also, when you service the pump, remove the cir-clip holding on the impeller - see
http://c34.org/wiki/index.php?title=Why_do_some_of_our_engines_have_different_Oberdorfer_sea_water_pumps_than_others,_and_what_about_that_cir-clip_%22holding_the_impeller_on%22%3F

Ken

[Ron Hill]

kable : You are 3 hull#s away from my 1988.
 
Contact DEPCO (800-445-1656) and get a new paper (very thin) gasket.  Then remove the cover plate (4 machine bolts) clean and inspect the inside surface of the plate to make cure it isn't worn or grooved. 

Look in WiKi and see the "how to" of your Oberdoffer pump and that gasket replacement.

A thought

[kable]

These are great replies everyone.

I will for sure clean this off, pull it and replace the seal again.  The o-ring face plate intrigues me as well.
I will search for more salt that could have possibly sprayed everywhere.

Just starting to dig into the engine area.  Really looking to learn and do as much as I can.

Ron, been reading a lot of your posts (and Stews), pretty cool my boat is close to yours so that I can make assumptions following what you have already done.

Thanks,
Kable

[kable]

Ahhh... Just pulled up some pictures from my survey and it does look like the salt crystals are new.  There must be a leak.
-kable