Fresh water after market flush

[torcano]

I just bought a boat in which the previous owner installed a fresh water flush system that he states he used religiously after each time he used the boat. He purchased the boat after 4 years of use in salt water without a flush. I just have changed the manifolds and risers. He told me to flush the engine after each use but only after the engine has cooled down. Does this make sense? Why does the engine have to cool down? This is system appears to just passively circulate water using the pressure from the dockside water faucet. It hooks into the cooling system with a Tee valve on the bottom of each engine. Is this worthwhile to continue flushing the engines after each use?

 

[tpenfield]

Re: Fresh water after market flush

I am not sure that there is any scientific evidence to prove or disprove that it helps. Since it was run for years without a flush, maybe not.

 

[Philster]

Re: Fresh water after market flush

Flushes are only completely effective on warm engines (with t-stat open). Without the t-stat open, then the engine itself isn't getting flushed.

That's fine if you don't mind having the heads rot out, leading to hydrolock which = complete engine death and requires a rebuild or new engine.

Most wise, salt-water boaters make an effort to flush the engine while she is as fresh from being shut down as possible; i.e., when she's good 'n' warm so that the t-stat is open or can open with a little running! Sometimes, very cold hose water on a cool engine will result in the engine never popping the t-stat. This is not good.

If the connection points are where you might get burned by a hot engine, they can be extended and mounted somewhere else, even as a fitting on top of the deck. That's the way to roll.

 

[torcano]

Re: Fresh water after market flush

The fittings are on the deck so there is no problem hooking them up. Philster, so you are saying the exact opposite of what I was told by the former owner. Even though the engines already have the first 4 years or running on saly water withouit flushing, do you really think there is benefit to flushing with fresh water so many years latter? The boat is 10 years old. I suppose it can't hurt.

 

[bruceb58]

Re: Fresh water after market flush

You are a least flushing out the manifolds which get the most corrosion.

The reason you don't do it with the engine running is that your raw water pump is in the drive so you would just be sucking up more salt water. I would just do it with the engine warm. You might get a little water to run through the block before the thermostat completely closes.

 

[MarkSee]

Re: Fresh water after market flush

Torcano: Just to be sure after reading your response in the other thread having to do with someone installing a fresh water cooling system: If you're asking about continuing to use a "fresh water flush system" the po installed then that can never hurt. If that 'system' is actually a fresh water cooling (fwc) system that includes an exchanger, then him installing that after 4 years of already being in salt water was after the appropriate window as is indicated and explained in the other thread.
Mark

 

[torcano]

Re: Fresh water after market flush

Sorry for the confusion. This boat was a raw water cooled boat and the previous owner did not install a fresh water cooling system only a fresh water flush system that where he put a tee connection into the cooling system. I understand that if the motors are running the drives will continue to draw in salt water. I assume the the fresh water just passively circulates through the channels using the water pressure from the hose. Doing it on a warm (not running) engine makes more sense to me. I don't know why the previous owner told me to do it while the engine was cold. I wanted to make sure that I was missing something that could damage the engine while flushing it while still warm. Thanks for all the advice.