350 MAG - RWC Flush or Not?

[Rocket]

I would like some opinions on Flushing of a RWC engine. During my delivery, the technician showed me the port to flush the engine, but advised that we dont need to do this all time. I watch people at my marina and dont ever see anyone flush their engine, assuming they have RWC. So what is the real scoop on this? I am doing some damage by not flushing them after every outing?

Another interesting conversation I had was with a Marine Max dealer in Florida. On vacation, we stopped in to look at some searays and the salesmen advised that the Horizon FWC engines only protect the block, not the exhaust manifolds. He said that is rare they corrode in the blocks and that Horizons are really not needed.

If i do need to flush them daily, would a FWC conversion help me? By the way, we boat in salt water.

Thanks in advance for your input.

 

[Go Aweigh2452]

I would like some opinions on Flushing of a RWC engine. During my delivery, the technician showed me the port to flush the engine, but advised that we dont need to do this all time. I watch people at my marina and dont ever see anyone flush their engine, assuming they have RWC. So what is the real scoop on this? I am doing some damage by not flushing them after every outing?

Another interesting conversation I had was with a Marine Max dealer in Florida. On vacation, we stopped in to look at some searays and the salesmen advised that the Horizon FWC engines only protect the block, not the exhaust manifolds. He said that is rare they corrode in the blocks and that Horizons are really not needed.

If i do need to flush them daily, would a FWC conversion help me? By the way, we boat in salt water.

Thanks in advance for your input.

Since you already are in saltwater, it would be a waste of money to go with FWC now... as far as the HO's, they are ceramic coated so that would slow down any corrosion issues. I would think Merc knows more than your local salesman personally... They certainly warrant the HO great...

 

[tphinney]

Your sale's guy is an idiot; in salt water you should flush it everytime you get back to the Dock. it will extend the life of your block and all components that are raw water cooled.

Most boats sold into the Salt water environment that are not trailerable are usually FWC not RWC. if you ask you're slip mates you will find this to be true and the reason you don't see them flushing is cause they don't need to.

everytime I get back I flush for no less than 10 minutes to completely flush the whole system of as much salt as possible. Hopefully by being diligent I will get more than 5 years/ 500 Hours out of my block and manafold which seems to be the average for folks who don't flush everytime.

 

[Alex F]

This is very interesting subject. I also have never seen anyone in the slip flushing the engines. One thing is inboard with V-drives that has flushing system installed, but another thing is I/Os. I doubt you’ll ever see anyone jumping in the water to put the earmuffs on flush and jump back in to take them off.

I also have the flushing system on my 320 and was planning on making a good use of it. After the purchase I was talking to one mechanic and he said that damage is mostly done if the boat is out of the water when salt dries and eats the metal. So, for the boats that always in the water it’s not that big of a deal. Granted, having the boat sitting is fresh water is much better that being in salt water, thus I think it will only do a good thing to the motor if you flash it. I’ll be looking to change few things around to make flushing convenient and quick by running a connecting hose to the stern locker next to the fresh water connection there now. This way I’ll connect both hoses in one spot and just run the engines. This will be a short-term solution, where a long-term solution would be installing PERKO valves to make it complete simply turn key flushing system.

However, when we talk about boats on trailers flushing is a must in my book. Some or most of the water is drained and salt will begin doing the damage. Since the boat is on the trailer everything is right there to do it right. So, flushing the engine for 5-10 min and spraying the trailer with fresh water will only expand the life for your rig.

I’d love to hear opinions from more experienced skippers.

Alex.

 

[Rocket]

Tom - What is odd is that when i purchased this boat, i was able to choose from 10 available 320's. All of them had RWC engines. Why would they order them like this, knowing that they will end up in salt water?

I am not trying to skim on my maintenance here, just trying to understand why many people with RWC engines dont flush them, and what their long term experience is.

 

[Go Aweigh2452]

I keep my boat on a trailer so my views are different. I back into a lake close by and run the engine while it sits on the trailer for a few minutes even though I have a HO and an air flush system installed on the engine. The trailer requires fresh water to slow down rust...

If the boat is left in the saltwater, the engine should be OK as discussed previously. I would suspect the new 320's coming in with RWC is just a way to keep the advertised prices down and have you buy the FWC through the dealer which would be a good moneymaker... for them.

 

[estebanj]

I have a RWC 350 MAG MPI with Bravo 3 and I flush after every outing. I'm in South Florida in salt water. To make flushing easier, I added a Perko FlushPro with remote water inlet so I don't have to open the engine room. I just connect a garden hose to the remote inlet in the transom.

How does the flush port in your engine works? Where is it? I'm just curious as to how it works. I pressume it does not allow flushing while in the water.

Esteban

 

[Go Aweigh2452]

If you have a separate RW intake, you can add a fresh water tap to allow you to flush while on the water. I cut off seawater and plug in the hose to the orange quick disconnect in the photo below. Works great... But then I can also air pump out any excess water so no raw water ever stays in the engine...

 

[2000SEARAY280SS]

GA 2452 When you use the air flush is it after the water pump? I would worry about damaging the pump if the air is pushed from the suction side.

 

[Go Aweigh2452]

GA 2452 When you use the air flush is it after the water pump? I would worry about damaging the pump if the air is pushed from the suction side.

The air flush system was designed by Merc... Here is a better photo:

You can see the two green pop ups on top of the engine and the orange colored tube at the bottom. The excess water drains out the orange tube and the green pop ups, pop up when pressurized. After drainage, pull the release valve next to the blue covered air valve. Totaly flush, 1 minute...

 

[Rocket]

I have v-drives, so in order to flush the engine, i need to close inlet seacock, and hook up a fresh water hose to the quick connect that was installed by merc. Once the flush is complete, i disconnect the fresh water and open the seacock. This can be done in the water

What i am also reading here is that since the boat stays inthe water, and i dont drain the engine from sea water, i am ok?

 

[Nehalennia]

Even though it's a VP part, I am instrigued with this kit. It should work just fine on a V-drive setup
QL Neutra-Salt Engine Flushing Kit

 

[dpmulvey]

I am astounded at the answers from "knowledgeable" folks at MM and mechanics.

SALT IS THE ENEMY! Period.

The boat has no idea if it is in a rack or in the water. The RWC cooling water will drain to the lowest point and sit. The remnant salt will cling to the metal regardless of the boats location.

RWC to FWC conversions can be safely done up to 100 hours on the engine; 150 on the outside. The antifreeze has corrosion inhibitors. Full system is better than 1/2 system especially if you have the dry exhaust riser. Don't get me wrong, there is damage already done. To convert now is to minimize the damage and prevent more. It will never be new.

The Horizon is COMPLETELY FWC. The Raw water flows from the intake through the heat exchanger and out via the exhaust riser elbow.

The FWC conversion will add about 100 pounds per engine, and cut down a TON of work space you currently have to get to the engine. You don't get something for nothing.

The conversion may or may not be worth the money to you. Only you can answer that. Pesonally, I would install a flush kit in the transom and flush the engines while you are tying up before I upgraded. That's just me.

HTH

 

[2000SEARAY280SS]

The air flush system was designed by Merc... Here is a better photo:
..... Totaly flush, 1 minute...

I was thinking about trying something like the air flush for my 2000 5/7's. I decided against it and went with the perko plastic flushers. Never heard of that option before sweet.:thumbsup:

 

[tphinney]

Rocket;

I can't tell where your at; but here in Tampa very few folks have the money to be in a wetslip (they are a premium) most Dry stack or like me are lucky enough to live on the water and have their own lift. So with that said if the boat is coming out of the water anyway FWC doesn't mean all that much since it only take about 10 minutes to flush the boat.

most folks who have their own lifts (and actually care about there boats) will spend more time hoseing it down to get all the salt off the deck, wind screen, rail, cleats, vinyl, etc than the mear 10 minutes it takes to flush. If their in a Dry Stack the flush and spray off is included in your monthly rental rate....

(sorry for the late reply)

 

[Rocket]

Tom - I am in Long Island NY and we are in wet slip. I am going Flush each engine diligently. You make a great point. I spend close to 1 hour cleaning the boat after each weekend, 10 minutes to flush will not make a differance. I need to find a better way solution to the seacocks in this boat. Very difficult to reach them.

Thanks for all your help.

 

[SteveMoffat]

My '91 Sundancer 290 has been in saltwater here in Bermuda since new. We have a high salt content in the water, however, it's RWC'd and has never been flushed out. I have changed the exhaust risers once, 4 years ago and have no issues with cooling or leaks.

I will be re-powering at the end of this year however, and will be going with a closed loop cooling system.

Steve

:grin:

 

[topgun1185]

This is a great thread, according to the merc manuel it recommends flushing all motors every time. Of course it's a great idea but a little time consuming especically around hot motors. Several thought's I have. 1) In order to reach those out of the way seacocks.I recently bought a tool from snap on that is used to help position serpitine fan belts. It is basicaly a 1/4 rod around 30" long with a screw driver plastic handle on one end and a "F" type bend in the working end. All the valves have yellow plastic coating witch after you cut back will reveal a 1/4" hole. Just use the tool with the "F" end inserting it in the handle of the valve and you have the leverage and reach to make the job really easy. 2) installation of a flushing device is easy and usally inexpesive and worth the time savings attwood make one that is installed after the sea strainer and does not require to close the seacock. 3) In a above post is a vp nutra salt product. I installed the system on my boat and have been using it for 3 seasons now but can't tell you if it works only time will tell. i will tell you the solution is $40.00 a gallon and it goes fast. 4) MM mechanics are a joke tell told me hoe to flush the motors completly wrong. According to the manuel you must close the seacock, must run the motor, must not run the water into the motors for more then 30 seconds before starting the engins in order to prevent water injesting back through the exhust into the motors. Hope this helps and good luck!

 

[Hampton]

I'm thinking up a plan for my 8.1's. I plan to run two 5/8", stiff hoses from the transom locker (Water manifold) to a 1" ball valve attached to the top of the sea strainers on each side. I will install two hose adapters to the manifold in the locker. I have two garden hose attachments at my dock. I'll hook both up, and then open both lines to one engine and flush it for a few minutes, then the other. Same for genny and A/C.

So, each engine will have the flow from 2 standard garden hoses for flush. I may have enough flow to allow me to rinse the engines without closing the sea cock. There will be flow into the engine and out of the sea cock at the same time. I'll have to taste the exhaust water to see if it runs clear. If not, I'll just have to close the sea cocks. There will be no risk in trying this since the sea cock will still be open. If the engine draws more than 2 garden hoses provide, it will just take the rest from the sea cock.

 

[topgun1185]

Why run double hoses just tee off each other with a valve to flush one at a time or tee off after the hose bib if you have enough pressure. Also I really think you have to close the sescocks especically if you dock in salt water since no mater how much pressure you have you are still going to suck up water through the strainer.