Flushing motors, or closed cooling, or neither?
 

With 502MAGs and the boat staying in salt water 24/7 (never hauled out or lifted), is it necessary to install motor flush kits (or install closed cooling kits)? I'm confused now.....I'm hearing both.

I've heard from more than one place that if the boat is never out of the water that running sea water through the motors will not cause long term damage and that the what causes the corrosion to start is when air is inserted into the equation.

About 15 years ago, I had a Sutphen that I kept in a high and dry and never flushed it:rolleyes: After 3 or 4 seasons, the engine locked up one day and the oil was chocolate milk. Although it's a PITA ya gotta do it (flushing that is!):D :D

Craig.....this boat will not be out of the water, always in the water. So the question is if it is never out, do you need to flush?

I'm sorry, I misread your post:rolleyes: I would think that those people who have said that you don't need to flush have closed cooling, but flushing will extend the life of the components that would still be exposed to the saltwater (mainly the exhaust manifolds/risers).

I'm sure that someone more knowledgable will chime in here, but I'll postwhore until then!:D :D

Yes....that is true, and closed cooling doesn't fix that issue does it......? Only a dry exhaust system would solve that.

Hey Nort,
Looks like we are the only one's looking at this one!! Ask the question over at cabincruiseronly.com :D :D :D

I think others are looking but have no opinion or don't know......

if your engines are in a saltwater environment it is always best to flush them w/ freshwater.

Nort, i'm sure someone will know first hand what the correct answer is but heres my take on this. The cooling systems in our boats are not 100% sealed. Meaning that water will eventually leak down and settle at either the lowest point where it cant leak anymore or it will be even with the water line of the boat. that being said i would imagine that air is still introduced to the cooling part of the closed system and thus you have the possibilty for corrosion. my biggest concern would be the upper risers and maybe a part of the heat exchanger depending on how the water is getting out of the system and how things are mounted on the boat/engine. I would play it on the safe side and flush it. Whats the worse that can happen? you spend a little more time on the boat and prolong the life of the parts? :)

Even if you put a fresh water kit in, I would still flush the salt water side if you can. If you're using raw water cooling (Like I am), I flush it when ever I can. I'm on a mooring so It's a little harder. I rigged something up so I can bring a 5 gallon container on the boat with fresh water, and hook it up to my water intake. I also use Salt Away in that water, and when I flush it by hose. I only do that 5 gallon setup when I know I won't be using the boat for a few days. I also try to put the boat on the trailer a couple of times throughout the season to give it a good flush and a cleaning. I check all the running gear as well. I've heard that salt water theory too. Who knows if it's true. I have friends who keep their boats in all season, only flushing in the fall, and they seem to be getting up to 5 years with no real problems. Luck? Check out the Salt Away website. They have more on flushing.

Being a cruiser kind of guy for the last couple years (cabincruiseronly.com, very funny), raw water boats that stay in the water definitely corrode fast, both the iron and aluminum parts. Most of my raw water cooling friends that flush have very little trouble. This also cleans the manifolds and risers (especially important with aluminum).
Closed cooling also works well, especially if you get a heat exchanger with the capacity to cool the manifolds as well. If you get a closed cooling kit, be sure to check to see if it's sized for manifold cooling. I think virtually every exhaust manifold, except Imcos, can be plumbed tis way.
Gary

Hey Nort,
You could just move to MO and boat with us on LOTO instead!:D

I flush mine everytime I'm in salt water. PITA but it's a necessary evil:( . A full closed cooling system is the only way to go if in salt. It would probably pay for itself in a few years.

I'd flush it even if it is a closed system.... if there are dissimilar metals connected by salt water... electrolysis will eat it alive... also check and change the zinc sacrificial anodes often.... Another problem is if someone has shore power close by.... if it is "leaking" electricity into the water.... you will suffer from it too. Even if you have a glavanic isolator in your shore power.... your neighbor could be causing corrosion on your outdrives.I'd invest in getting a hydro hoist.

Ok Guys I'm new here.... what does PITA and ttt mean?

Pain in the a$$, to the top

I have closed cooling and still flush it out everytime.

Thanks Checkmate

Closed Cooling
 

I have a 90 5.7 Mercruiser that I put a Monitor Products heat exchanger/closed Freshwater cooling system on i. It runs antifreeze in the block and manifolds, the Salt water is dumped into the risers.
It was a freshwater boat 3 years old when I got it, in 94.
It has lived 6 mos per year on a mooring in Casco Bay, Maine, as salty as it gets! I rusted thru one set of risers (these are salt water cooled, and were stock cast Iron). They lasted about 4 years in the salt, with one muriatic acid rod-out cleaning. I bought a set of take off SS cast stock Mercruiser risers on Offshore only(which I found the day I was searching, and have been a member since.. great board!)

The benefits of FWC are many, the manifolds and engine are 14 years old, and have no scale in them, the engine runs nice and cool, with nice temperature control, and there is no internal corrosion. Winterizing is very easy, as you don't need to drain and flush, and wonder if you got it all, just pull the ends off the heat exchanger, and pull the hose off the power steering cooler, and drain the risers with two petcocks. I usually flush the engine in the fall, but not always. I think the $600 that the system cost me has paid for itself many timews over in manifold and engine life. I used a system with my Alpha that used the Sterndrive pump, no seawater pump was added. I added an overheat buzzer/oil pressure buzzer when I did the conversion, it has saved me once from mussels clogging my intake. Best $50.00 I spent!

I think most people run raw water systems because the manufacturers want to keep the costs down. Most expensive yachts that run Crusader engines (GM) use FWC.. it is just cost that keeps them out of speedboats. In my opinion(and some marine engineers I know), you are crazy not to install a system if you are running on the ocean. That said, I ran a Volvo for nine years raw water cooled and it was okay.. though, it did go thru head gaskets, and a manifold.

My .02

Dave Leonard

Closed Cooling
 

I have a 90 5.7 Mercruiser that I put a Monitor Products heat exchanger/closed Freshwater cooling system on i. It runs antifreeze in the block and manifolds, the Salt water is dumped into the risers.
It was a freshwater boat 3 years old when I got it, in 94.
It has lived 6 mos per year on a mooring in Casco Bay, Maine, as salty as it gets! I rusted thru one set of risers (these are salt water cooled, and were stock cast Iron). They lasted about 4 years in the salt, with one muriatic acid rod-out cleaning. I bought a set of take off SS cast stock Mercruiser risers on Offshore only(which I found the day I was searching, and have been a member since.. great board!)

The benefits of FWC are many, the manifolds and engine are 14 years old, and have no scale in them, the engine runs nice and cool, with nice temperature control, and there is no internal corrosion. Winterizing is very easy, as you don't need to drain and flush, and wonder if you got it all, just pull the ends off the heat exchanger, and pull the hose off the power steering cooler, and drain the risers with two petcocks. I usually flush the engine in the fall, but not always. I think the $600 that the system cost me has paid for itself many timews over in manifold and engine life. I used a system with my Alpha that used the Sterndrive pump, no seawater pump was added. I added an overheat buzzer/oil pressure buzzer when I did the conversion, it has saved me once from mussels clogging my intake. Best $50.00 I spent!

I think most people run raw water systems because the manufacturers want to keep the costs down. Most expensive yachts that run Crusader engines (GM) use FWC.. it is just cost that keeps them out of speedboats. In my opinion(and some marine engineers I know), you are crazy not to install a system if you are running on the ocean. That said, I ran a Volvo for nine years raw water cooled and it was okay.. though, it did go thru head gaskets, and a manifold.

My .02

Dave Leonard

The Mercury closed cooling kits are $1500, plus 4-5 hours labor (each). Not seeing the value of that yet......

Still need to flush to save the exhaust parts! Thanks for everyone's input. I'm being edukated here! :D :D :D

Norty,

My folks have a cruiser that stays in the water in San Diego.. It has closed cooling and they didn't flush the motors at first... After about 2 years they had to replace the exhaust manifolds because they had corroded so bad. Now they flush the motors everytime. Also, keep an eye on your drives..My folks had coral start to grow on theirs because they didn't get painted and it was a ***** to get them cleaned out..

The worst part of leaving it in the water all time is the corrosion on the outdrives and parts..... my boat was in the salt water all it's life.... and it was flushed and washed down every time it was put on the trailer at the end of the day.... and I still had electrolysis under the drive trim indicators and anywhere stainless was touching aluminum... I still say....if you don't want to tow it.... get a hydro hoist... where are you planning on mooring your boat? Ventura? MDR? Newport? If your boat is under 40' you can have it put on a "rack" at Lido boat yard in Newport..... let them drop it in the water for you.... and then take it out when you are through boating. Just a suggestion.....

If it has notbeen said already DO NOT add closed cooling to a motor that has not had it since new.

Jon

What is your theory on "not adding closed cooling to a motor that has not had it since new"?

The problem is that the motor is already scalled up. So the rust breaks free and clogs up the exchangers. You also need to make sure you use different pullies or the oil will not cool properly as the flow drops off through the oil coolers and makes them less efficient. The only way to do it is to break them down and have the blocks dipped to remove the rust IMO.

Jon

I would definatly get closed cooling on them however. Unless of course you want them to corrode and then get some motors out of RWD and really make that thing screw :D:D

GUARDIAN
 

Go to MST Guardian Web site and look at the BP HP System. A quick, no engine running flush system that can cycle through each engine, genset, ac etc.

There is a transom mount and will power flush the engine and exhaust components. They have a scale remover that you use after installing the system that removes rust scale accumulation and cleans the engine/exhaust .... after that... simple flushing.

I use the system and love it.

We may be setting up as a dealer due to the fact the system works so well in value for the dollar. It was an easy install.

I installed the Guardian system on the 502 in my last boat. I am not a motor head in any way, but had no problem doing the install. And it made flushing so easy. Just plug in the hose, turn the water on and listen to it do its thing. The real advantage for me was being able to flush the motor with the boat still in the water. That way I did not have to always wait for a wash rack.

Sounds like just what you need Nort.

Engine off flushing
 

Agree Macklin, that is the best part, no need to run engine, wake neighbors, in water flushing, etc.

I use the 'Salt Shaker' which has a timer and cycles through each engine with one transom connection.
Trailer is set up with onboard water for flushing using the aux power on the 7 pin connector, a pump timer & a recoil hose to attach to the transom. This allows flushing immediately after pulling boat out and washing salt water from boat/trailer.

Re: Flushing motors, or closed cooling, or neither?
 

You might try a cooling system filter in such cases. Many people are not aware of such devices, but GM actually sells them. They are used by large diesel truck engines, and have heater hose size fittings on them. The filter looks like a PF-30 oil filter (about the same size, but different gasket and filter media). I put one on a old Buick I bought, in which the previous owner never changed his coolant. Talk about rust and scale! The filter worked like a charm, and the cooling system stayed very clean. I believe the filters are available from Napa Auto, and you may be able to get the filter housing there, too (otherwise check with a GM truck dealer).

Michael

Re: Flushing motors, or closed cooling, or neither?
 

There are closed cooling kits without Merc logos for a lot less--and we all know that Merc doesn't manufacture them--they "outsource" to some 3rd party
I'vee seen them for around $400

Re: Flushing motors, or closed cooling, or neither?
 

I have added closed cooling to three different boats which were fresh water boats to begin with and had zero problems. I did flush them a couple times initially with system cleaners but that was about it.

Re: Flushing motors, or closed cooling, or neither?
 

I keep my boat in the water too during the summer season, and when installing new engines I decided to install SuperFlush from http://www.superflushsales.com/
and I am very happy with it. Flushing couldn't be easier, you don't have to run the engines during flushing, very little added weight (compared to closed cooling) and the entire engine is flushed including exhaust risers/elbows.
I believe it is pretty much the same system as the MST Guardian, but I think MST Guardian went out of business based on the info on their web page:
http://www.mstguardian.com/index.html
under August 05 Update.

Re: Flushing motors, or closed cooling, or neither?
 

Sorry. I now realise this is an old thread.

Re: Flushing motors, or closed cooling, or neither?
 

flush....flush.....flush...it's a must in salt water