Salt on Alternator - Leaking Heat exchanger gasket

Mighty Majestic

New Member
Sep 8, 2017
14
The Emerald City - Seattle, WA
Boat Info
2003 SeaRay Sundancer 380; AB Dinghy
Engines
Mercruiser 8.1s Horizon
Boat: 03 Sundancer 380; Gas MerCruiser 8.1S Horizons
Owner for 33 months, Moored in freshwater, cruise in salt water

Aliya here. New to the forum but have met many of you at SeaRay events. I'm pretty darn handy and have fixed the generator, done electrical and crawled in spaces you shouldn't be able too. So... here's the question.

Our Port side heat exchanger seems to be leaking or sprinkling salt water on the starboard engine, near belts AND forming salt stalagmites on the port alternator. Seriously not good. The rubber gasket looks to be 4" instead of 3.75" per specs.

We ran the engines in neutral at 2500 RPM so I could take a look at them, it looked like it was just getting moist under the gasket area, above the two hoses. We are thinking that if we run port closer to 3700 RPM might be when it's sprinkling or spraying the area. Did not try but probably will once I get ear plugs.

We are in Roche Harbor right now waiting on parts to arrive. It seems pretty straight forward to remove the bolt, cover and 0-ring and old gasket with new. I've looked online for any YouTube videos on this and found something similar but not exact.

One video mentioned, closing the seacock. Maintenance and parts guys, have not mentioned I need to do that. The seacocks (I don't think) have ever been closed.

1) Do I need to close the seacock? Can I change gasket with it open?

I'm planning on covering the alternator and hoses near the gasket before letting the water out of the cylinder and into a bucket of sorts.

2) And helpful hints on changing the gasket? It seems pretty straight forward.

Thanks SeaRay-ers!

gasket.jpg
 
I did mine in the water. No water came out at all, so it must drain down to a lower point in the system
The repair is about as simple as it gets
 
Good luck and you should exercise your seacocks at least once a quarter to make sure you can close them in case of a catastrophic event...
 
I'll echo what previous posters have said. Additionally, you can get some Salt Away to spray on anything you think my have been hit by salt water. It's good stuff.
 
I'll echo what previous posters have said. Additionally, you can get some Salt Away to spray on anything you think my have been hit by salt water. It's good stuff.

We just purchased some for the outside of the boat and the Marine store here at Roche just mentioned something similar about SaltAway so I'm going to use it today in the engine area. He also suggested spraying the alternator with CorrisionX, which I happen to have bought weeks ago for something else, so I'll be doing a lot of cleanup work before parts arrive on Monday.

This sounds a heck of a lot easier than the electrical work I did on our generator. So I'm happy to have one more easy thing I can do than pay someone $125/hr!

I'll post update when it's complete or if I have more questions. Thank you to all.
 
(Parts Diagram attached)

Update: Gaskets, o-ring & screws replaced. All working well, but did not fix the salt on alternator problem. Looks like it might be my starboard engines saltwater pump / impeller.

For anyone who might care, here's the part numbers I ordered for the heat exchange.

2003 SeaRay Sundancer 380 - MerCruiser 8.1S Horizons
Gasket cover - 3.75" diameter (black round rubber flat ring) = 891716
o-ring = 8M0039163
screw = 98261

(see diagram - lines 32-35 -- view attachment)

I cleaned the heat exchange brass end piece with "Bar Keepers Friend" - best stuff ever, and saved myself $120 each.

heat exchanger specs.jpg
 
Best fix that pump asap, that bearing, shaft, seal assembly will walk out of that pump, taking the belt with it
 

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