Fresh Water Cooling System Question

[bob]

I just purchased a used 2000 240 DA (5.0L, Bvo III) that had only 150 hrs--all in fresh water. I will be berthing it in brackish water and using it primarily in costal waters--obviously salt H2O). Prior to launching, I'd like to have a "fresh water" cooling system installed to protect the engine. Has anyone had any experience in having an after-market cooling system installed? Is it worth the extra money for a "full" as opposed to a "half-system? " Are any after-market brands better than others?

 

[estebanj]

I think Monitor is the most popular brand. They are supposed to be DIY, specially the half system. Although, I have not installed one.

You can also consider an engine flusher vs. adding FWC. Flushing after each outing with fresh water (and sometimes adding Salt Away or similar) will also keep the engine in good shape. Keep in mind with FWC, part of the system will still be RWC (risers, elbows, heat exchanger). FWC normally adds protection to the block and exhaust manifolds.

Esteban

 

[bob]

I had heard of a fresh water flush and contacted Mercruiser's customer service dept about one. I was told that only certain engines have that as an available option--mine, a 2000 5.0 L, evidently doesn't fall into that category. Thanks anyway.

 

[estebanj]

You can add a flusher to almost any engine, specially on yours which is a Bravo 3 and has the water pump in the engine and not the outdrive.

You can go with something like the Perko FlushPro, or a SuperFlush system, or something custom made.

On the Perko or custom, what you basically do is tap into the raw water line coming to the engine and add a valve to shut off raw water when you flush.

BTW, I'm not trying to steer you away from FWC, just making you aware of options.

I have a RWC 5.7 MAG MPI with B3 with the Perko FlushPro.

Esteban

 

[estebanj]

Take a look at this post on flushing options.

http://www.byowneryachts.com/forums/phpBB2/viewtopic.php?t=2684

I said I went with Super Flush, but actually went with the Perko.

Also, in case you need it, here's the web site for Monitor FWC kits:

http://www.monitorpro.com/

Esteban

 

[bob]

Thanks for all the info guys. Naturally, the more info I get, the more questions I have. I'm thinking of putting in a "half" system.

Are the "flushing" systems as good as an installed fresh water systems? Would the engine flush devices still work in conjunction with a half system, at least for the risers & exhaust manifold?

As my pevious outdrive experience has been limited to Alpha 1's, I didn't realize the Bravo 3's don't have an internal water pump. Where would the raw water be picked up then? How would a fresh water system benefit the outdrive, or is that a non-issue? Sorry, my ignorance is showing guys.

 

[estebanj]

Flushing won't be as good as FWC b/c you're still running raw water through the engine.

Adding a flusher to a FWC engine is even better b/c you are then flushing the RWC part of a FWC engine. You need to consider cost, installation, and convenience when making your decision.

In a B3 unit, the raw water pickup is through the outdrive into the water pump mounted on the engine. That part (the outdrive passage) will always be exposed to raw water. Some people have flushers that allow back flushing to the outdrive when done flusing the engine.

Esteban

 

[bob]

Esteban:

I wasn't aware of the salt-water corrosion problems with the Bravo III outdrives until just the other day--after I bought the boat, naturally. Now, I'm getting a bit worried about future maintenance costs about the outdrive unit. That's why I want to get the best protection for it which would include a flush. Do you know of any flush kit manufacturers that allow for an installation along with a fresh water system? Since my boat will be in a slip for the season, I wonder if a flushing kit would allow it to be used while the outdrive is submerged?

 

[estebanj]

The best solution for B3 units is dry storage... can you install a lift in your slip?

If you have to wet slip, I would consider both FWC add-on kit (to help the engine block) and a flush kit for the raw water components. However, neither one of these helps with the corrossion on the outdrive components.

For that, you need to maintain and enhance your anodes and mercathode. Consider adding a 2nd mercathode controller (assuming you already have one) or adding the transom mounted mercathode system (pucks).

Also, make sure all your anodes are replaced when needed and make sure you have all of them installed, including the prop shaft one. For salt water, they should be aluminum.

Since you're in Maine and the boat gets hauled out half the year, you're not in so bad a shape. The B3 will last many years with proper maintenance. Unlike an inboard, where you can do inspection when the boat is hauled out at the end of the season, I would inspect your outdrive half-way through the season to make sure it's all right. You can do this while at anchor in shallow water tilting the drive up.

Don't lose sleep over this.

Esteban

 

[bob]

Thanks for the re-assurance. Unfortunately, the marina where I berth the boat has "floating" slips, so a lift would be out of the question.

I already have a mercathode system installed, but will talk to my marine mechanic about adding another or the transom system you talked about. I think my anodes are zinc since the former owner operated strictly in fresh water, so your suggestion of replacing them with aluminum is probably a smart move.

FYI, my marina is located on the Saco River, about 2 miles from the ocean. Two miles further upstream the river is cut off by several dams, so the river is tidal, but still has an influx of fresh water spilling over the dams.

About the warmest water surface temp in the river is about 75* and the Gulf of Maine waters in my are usually run 60-70* during the boating season; (May-Sept).