Fresh Water Rinse Manifold '05 340Da

John, I'm 100% with Frank on the plastic fittings. I just dont trust them, especially in my region for the winter. Even by looking at your stern lock valves setup, even thoug all looks nice and logical, I'm thinking on having similar setup with bronze or brass fittings.
 
Thanks to all. I'll look for replacements on line.
 
frank
do you anticipate expansion b/c of engine room heat or b/c of environmental factors. around here (northeast) i'd imagine the winters would kill the interface btwn the metal and plastic, but in warm sunny florida??
 
Ron,

Both. The 2 materials are so different that I think both temperature differentials and the enviornment are problems. While you may think Florida may not be a concern, consider an engine room shut up on the hot sun for a week when temps get to 95 or so degrees....add 15 degrees for the shut up space, then you crankup and go boating in sea water that is 40 degrees cooler.

Then what about the hot part of the summer when the closed engine space may get to 120 degrees during the day and 70 degrees at night.

I just know that every time I try to use brass fitting and PVC together in Florida, I usualy have to repair the PVC at some point due to cracks in the threaded joint. So based on prior experience, I don't want plastic fittings in a below the waterline application on my boat

Besides, I believe the ABYC and USCG both prohibit plastic fittings in marine cooling systems, unless they are glass filled like Marelon fittings.
 
different coefficients of thermal expansion. makes sense! DO WHAT FRANK SAYS!!!:thumbsup::thumbsup:
 
Huge Success

I am searching on line for bronze fittings.

I temporarily installed one of my valve assemblies. One fit right next to the strainer, so I was able to test it out with very little effort.

Findings:

All findings with through hull strainer ball valve open (no need to enter engine room).

1) 2 hoses supply enough water to rinse up to 1000 RPM, 5.7 PSI water pump pressure, less than one minute total time to completely clear water (tested at exhaust, total dissolved solids in parts per million).

2) 1 hose supplies enough water to rinse at idle (650 RPM), 3.4 PSI water pump pressure, just under 2 minutes total time to completely clear water.

3) At idle with 2 hoses connected and strainer top removed, fresh water flows out top of strainer and completely rinses engine in less than 2 minutes (demonstrates excess water flow - Note: Water psi did not change even 1/10 PSI when strainer opened - indicates engine is not over-pressurized with fresh water - it simply flows out the bottom through the thru-hull).

4) Hoses disconnected, valves close at manifold in transom locker, engine run up to 3200 RPM and over 20 PSI water pump pressure, clear water rinse hoses show no tendancy to close, collapse, or distort in shape in any manner.

Implications:

1) No need to open engine hatch to rinse engines.
2) Complete redundancy for protection of normal engine cooling in case of single part failure (valves).

Procedure:

1) After docking, hook up two hoses in transom locker, turn them on, and open supply valves at manifold (hose connection valves) in transom locker.

2) Start one engine. Check for water flow (standard).

3) Open corresponding engine valve at manifold in transom locker. Check for water flow (standard). Rinse has begun.

4) Bump throttle up to 1000 RPM if desired to increase flow, increase rinse, and expedite process.

5) Taste water at exhaust after approximately one minute. When water tastes fresh, proceed. If not becoming fresh, decrease RPM to stop taking raw water in through strainer. Once fresh tasting, proceed.

6) Decrease RPM to idle.

7) Turn off one supply hose at manifold (and faucet, if desired).

8) Shut off engine.

9) Immediately turn off engine valve (at manifold), second hose valve (at manifold), or faucet. Turn off other manifold valves before operating engine if not already turned off.

10) Start other engine and repeat process.

What if:

1) I open wrong engine valve at manifold: Water discharges out bottom of boat and back-washes respective strainer - Possibility exists of filling muffler, risers, elbows, exhaust manifold and engine (one not running) if left unattended. Engine running does not get rinsed.

2) I forget to open fresh water hose valves at manifold: Engine does not get rinsed.

3) I forget to close engine valve at manifold when done: Nothing - Closed water supply valves block flow of air.

4) I forget to close fresh water valves at manifold when done: Nothing - Engine valve at manifold blocks flow of air.

5) I have failure of one of the valves at manifold: Nothing - See above.

6) I have a failure of some piece in the assembly which allows air into the system: Shut the ball valve in the engine room and proceed with safe boating.

7) I leave the engine valve open at the manifold and one or both of the garden hose valves open at manifold: Stop boating.

The key is to stop the air flow when finished rinsing so that the engine stays full of fresh water and so that it will draw salt water back in when started for the next day's boating. Failure to stop air flow will cause engine impeller to draw air, not cooling water.
 
Last edited:
tobnpr said:
Why not just use this?
http://www.outerbanksoutfitters.com/product/357260074msk.htm?bct=;cimotor-flushers

My raw water strainers actually have a gate valve with a garden hose connection built right in the access plate at the top of the strainer. Never used it though. I don't see the point in flushing an inboard that's FWC.
Click to expand...

The transmissions have salt water heat exchangers. The engines also have Oil coolers with salt water (I think). They have fuel coolers with salt water. They have heat exchangers with salt water. Your exhaust manifolds are cooled in salt water. Leaving salt water in all of these tasks your zincs (I think), and definately leads to early failure of many of these parts and frequent transmission failures, fuel leaks and possibly total engine destruction (exhaust manifolds)...

You can change these out every few years, take a chance, or rinse them.
 
john:
i agree wholeheartedly. BUT i dont think merc uses zincs in the heat exchangers (there are none on my old engines). that is a crusader thing. other than that, there is NO reason to not flush engines other than laziness!
 
I meant the zincs in the water. Since everything is grounded together (including the through-hull transom zinc), and everything is routed through the Mercathode system, it seems to me that salt in the raw water cooling system/manifolds... would eat up the transom zinc faster ($78 plus time or labor).
 
Guys,

I spent a hour searching on line for a good combo of bronze fittings to minimize the number required to re-finish this job. Anyone have a great source for bronze/brass plumbing? I'll need 1 1/4" T's, reductions to 3/4"...
 
Here:

http://www1.mscdirect.com/CGI/N2DRVSH?PACACHE=000000057271485

Would you like for me to come put them on for you too........!



MSC is a good source for about any kind of hard to find hardware. With HD and Lowes forcing so many smaller hardware guys out of business, they've been a super dependable source for some of the odd stuff I get into.
 
Thanks Frank and not-so-Newbie. And, why, yes, Frank. I believe there's at least one Diet Coke on our boat with your name on it.
 
After searching on line for another hour, I went down town to Panama Marine. Their prices were about the same. Each side costs an additional $90 or so to do Bronze in place of plastic. Female 1 1/4" T - $24. 2 1 1/4" barbed fittings - $17 each. A couple of bushings to get from 1 1/4" T to 1" Ball valve to 3/4" barb - $25 (including barb fitting). Tomorrow, I'll install the good stuff and take pictures.
 
Sounds you on the roll man. A quick question, how did you get the hoses through the ingine hatch, did you have to drill additional halls or was there existing one you could use?

Thx,
Alex.
 
Hampton said:
The transmissions have salt water heat exchangers. The engines also have Oil coolers with salt water (I think). They have fuel coolers with salt water. They have heat exchangers with salt water. Your exhaust manifolds are cooled in salt water. Leaving salt water in all of these tasks your zincs (I think), and definately leads to early failure of many of these parts and frequent transmission failures, fuel leaks and possibly total engine destruction (exhaust manifolds)...

You can change these out every few years, take a chance, or rinse them.
Click to expand...

Not criticizing, but the "I think(s)" mean you should obtain a service manual for you engines and learn which components are on which side of the cooling system. Granted every engine is different. I think that there's an underestimation on your part of the durablity of components on the sea water side. With the exception of the risers- where the extreme heat of the engine exhaust mixes with the sea water (perfect recipe for corrosion), most of these components will last for many years without "flushing". Of course, they still need to be removed/disassembled for cleaning regardless. I would be very surprised if your manifolds were RWC. Risers, yes- but not manifolds. I have a 6.0 Crusader in my Chris-Craft that has FWC manifolds AND risers.

Like I said, every engine is different. Only the heat exchanger (obviously), aftercooler, and transmission oil cooler on my CATS are sea water cooled. I guess rather than saying flushing is not necessary (and I still don't think it is), I could have better said don't over-estimate the benefits of it. Risers/manifolds on a gas engine still need to be replaced every 3 or 4 years on most engines (Mine above is an excpetion) regardless of whether the engine has been flushed or not.
 
I respect your opinion, but, like I learned with my 250, keeping it rinsed allowed me to drive that boat for 10 years without replacing anything due to corrosion. I never had any engine work done other than standard preventative mx. The 340's and other similar boats are having huge problems with exhaust manifolds corroding and transmissions failing due to corroded transm. oil coolers.

You're right, I don't know the exact flow of the raw water through the exhaust system.
 
Alex F said:
Sounds you on the roll man. A quick question, how did you get the hoses through the ingine hatch, did you have to drill additional halls or was there existing one you could use?

Thx,
Alex.
Click to expand...

I drilled new holes in the port side of the transom locker, similar to the ones that were already in place. That panel has no structural purpose, just a barrier. I also drilled one hole in the floor near two others. I put a plastic thu-hull bulkhead fitting in place with 4200 to provide a clean passage and good support.

There is a small compartment between the transom locker to port and the cockpit entry area. In that compartment, the swim platform shower is hidden. In the floor of that compartment, there are two holes with plastic through-hull fittings that allow passage of the water hoses and electrical systems from the transom to the engine room. That's where I drilled the hole in the floor.
 
Well, I have finished the genny flush and it tested good. I also replaced the plastic assemblies with bronze ones for the engines, and they tested good. I took some pictures, but I'll be at work all evening, so I won't be able to post them until tomorrow. The bronze fittings make the whole thing look very professional and quite durable. They cost like that too.
 
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