Fresh water flush with engine off.

[Doug Dodge]

I was just reading a comment Tony made about being able to flush the engine when off with the right exhaust.
My exhaust is thru the bottom of the hull. So water is introduced in a shower ring just before it exits the boat. So water running simply falls out.
I’m removing my fuel cooler, installing a 115 degree pump exit and was going to run a hose down to bypass the cooler (6CTA8.3)
Now I’m thinking this would be the perfect spot to install a hose connection to flush the engine out. It’s just after the pump so it does everything with no restrictions.
Any problems with my thinking?

Thanks
Doug
New Adventure

Topic

[Doug Dodge]

My set up is fantastic! Very simple and only take a couple of minutes (by myself) to flush with the engines off. Its so simple to do, I flush these engines every time I start a motor. I can do this because (as you can see in the pictures I posted) my exhaust is discharged directly through the bottom of the hull (NO Exhaust lift)(not common)

As for yours, its not the exhaust leaving the engine you have to evaluate, it how it gets out of the boat. Most boat use and exhaust lift . If that’s the case with yours, you can not do this with the engine off, because the lift will fill with water and cause a real problem next time you go to start the engine.

If you have an exhaust lift, you need to place the flush in the strainer lid or somewhere before the salt water pump and do it with the engines running.

Hope this helps

[Matt Lyman]

Hi Doug- I just ran into this string because my aftercoolers are shot and I’m trying to prevent the same issue with the next one. I love your setup. Hows it working?

I’m trying to evaluate my exhaust and if I can accommodate a similar setup. Attached is a pic and its all down hill from the inlet but mine doesn’t exhaust out the bottom, and is not as steep.

Thanks!

[Rob Schepis]

Steve, engine running — is there a reason you do not wish to introduce the freshwater BEFORE the pump?

[Steve wilson]

fresh water flush

I just purchased a 37′ back cove with a 8.3qsc / 600hp. I would like to do a fresh water set up like yours . My question is my engine has a 2 stage lift water muffler , can I ( engine running ) leave the thru hull open and attach a hose ( dock water ) pressure and flush my motor with out hurting it. Would it suck enough fresh water , to flush out the salt water .

[Doug Dodge]

Wanted to post a final update on my fresh water flush setup. As I planned, I installed it in the salt water line just after the pump. I can now do a complete flush in a minute without having to start the engine or touch the thru-hull. Works GREAT!

[firehoser75]

Yes, Kevin, once the work of that install is done, then it is even easier to flush! Well done.

[KevinS]

firehoser75 wrote:

Hi Doug,

I echo what Philip is saying about the benefits of freshwater flushing, well worth the small time and effort involved.

It is very easy to freshwater flush with the engine running. Only takes about 3-5 minutes of run time and the setup time (getting out the hose, etc.) would be the same as the method you are suggesting. It is easy to install a “hose connection” on the top of your raw water strainer and supply the dock water there. Added benefit is you can then backflush your through hull as well.

The only downside (unless running the engine is a downside for some reason), is ensuring that the correct sequence is followed, and even that can be avoided if you leave the through hull open (or partially open).

Looks like my photo went in upside down for some reason??

Just saying, sometimes simple is better??

Ah your “Thoroflush Cap” I used to have those on my last boat and just kind of copied them for an install on the present boat except runnig them to on deck Perko water bibs.

[Doug Dodge]

Here is a shot of the exhaust upside down and off the engine. the silver ring takes the water and cools the pipe then mixes with the exhaust gas as it showers out the holes in the bottom. This is sitting on an 8″ fiberglass pipe going directly out the bottom of the hull.

I want to do it this way because I don’t have a way to turn my engines on and off from inside the engine room. This way I’ll have 100% fresh water sitting in the important part of the engine all the time and it will be very fast and easy.

[marks737]

Here’s my quick disconnect set up on my strainers. Literally takes a few minutes to flush both engines and genny at the end of a run.

[firehoser75]

Hi Doug,
I echo what Philip is saying about the benefits of freshwater flushing, well worth the small time and effort involved.
It is very easy to freshwater flush with the engine running. Only takes about 3-5 minutes of run time and the setup time (getting out the hose, etc.) would be the same as the method you are suggesting. It is easy to install a “hose connection” on the top of your raw water strainer and supply the dock water there. Added benefit is you can then backflush your through hull as well.
The only downside (unless running the engine is a downside for some reason), is ensuring that the correct sequence is followed, and even that can be avoided if you leave the through hull open (or partially open).
Looks like my photo went in upside down for some reason??
Just saying, sometimes simple is better??

1 user thanked author for this post.

Kevin Lee

[Philip]

No problem with your thinking but I really can’t comment if it’s “safe” without some good pictures of your exhaust from turbo to hull exit from top and side angles.

Post some hi res in focus pictures of exhaust a long with showing where you want to inject fresh water and we can comment further.

Your effort to fresh water flush will pay off if time.

Phil

[Author]

Replies