Mercruiser 5.0L Advice required for flushing

[actros]

Hi all,

I am new to this forum and considering getting my first boat which is a 2009 Sea-Ray 205 with V8 Mercruiser 5.0.

I want to keep the boat in a saltwater marina and am concerned with the problems which may occur if I cannot flush the engine. The thing is I cannot find exact information regarding if there is a possibility to flush these engines in the water (I have heard of fresh water flush kits you can get?) Do these work? I see many other boats which are birthed in the marina and I assume they don't all have problems.
Another issue is that I believe the 5.0L is raw water cooled rather than having it's own seperate cooling system like the 4.2 so hence should be flushed every time?

Any advice / help greatly appreciated!

Thanks

Daniel

 

[Don S]

Re: Mercruiser 5.0L Advice required for flushing

Depends on which outdrive you have. Do you have raw water cooling or a closed cooling system with heat exchanger?

 

[actros]

Re: Mercruiser 5.0L Advice required for flushing

Hi Don,

thanks for the reply, the engine s raw water cooled and the strendrive is Alpha 1

 

[Don S]

Re: Mercruiser 5.0L Advice required for flushing

The flushing tees won't work when the drive has a pump in it like the Alpha's do. It will still pump water to the engine.
Flushing the engine without running it will not flush the engine, only the exhaust system.

If you plumbed in a way to start the engine with the water from the drive going overboard, and a hose used on the engine, then you could actually flush the engine with the thermostat open and the engine circulation pump working.

 

[actros]

Re: Mercruiser 5.0L Advice required for flushing

Thanks Don,

I'm trying to understand if actually keeping it in wet parking and dragging it out say 3 times per year for a good flush might be ok for it. I am not planning on keeping the boat forever maybe 2 years max so in this time I wouldn't expect too much salt corrosion?

 

[Pete104]

Re: Mercruiser 5.0L Advice required for flushing

Not in the engine. The drive may be deteriorated but the engine will be OK.

 

[achris]

Re: Mercruiser 5.0L Advice required for flushing

Many, many boats are berthed in salt water and never flushed. If the plan is to only keep the boat for a couple of years, enjoy your boating and don't worry about flushing it. P.S. leave the drive trimmed DOWN and the steering pointed straight when you are not using the boat. This will save the bellows. Also make sure to either replace all the anodes (and I would have supplementaries on as well) or (my preferred option) fit a MerCathode kit.

(I have seen 25 year old V8s, that have lived in the salt all the time, still going strong)

Chris........

 

[tpenfield]

Re: Mercruiser 5.0L Advice required for flushing

+1 to achris.

Salt water is not the scarey demon that some think. I'll have to admit, I only got 20 years out of my Mercruiser 7.4l engine in salt water before it needed a new head gasket. The internal passageways of the cooling system are still in good shape though.

Your best defense against salt is anodes, plentiful and frequently replaced. Flushing is not going to do much. Anodes are the key to success.

 

[mohead1]

Re: Mercruiser 5.0L Advice required for flushing

Ya know, Im glad to hear all this about the flushing and salt water old wives tales......Ive always been in lake/river water never salt (that is with my own boat) and wanted to take my "new" boat to florida on vaca but wont have a way to flush it at the condo area. I will pull it out and keep on the trailer, so its good to know Im not gonna start issues somewhere from a couple weeks of being on the salt. Sorry for the ignorance, just dont know nuthin about salt life, much......

 

[Loon-A-Sea]

Re: Mercruiser 5.0L Advice required for flushing

a salt water mooring related post and photo.

From my perspective, which is biased, I would say run away from the i/o. In salt water, the exhaust risers/elbows have a bad tendency to rust out from the inside.

http://media.photobucket.com/image/stern drive left down corrosion/eshepdog/P4270215.jpg

you would be amazed how quickly you can have a serious corrosion issue.

Good luck and best of wishes with your decision.

 

[tpenfield]

Re: Mercruiser 5.0L Advice required for flushing

That is a great photo (above) and shows what can happen if you do not keep up with the anode projection. The outdrive literally disintegrated due to galvanic corrosion. I would imagine that this boat was left in the water for a long time without anode refrash or use of the Mercathode system.

 

[Loon-A-Sea]

Re: Mercruiser 5.0L Advice required for flushing

That is a great photo (above) and shows what can happen if you do not keep up with the anode projection. The outdrive literally disintegrated due to galvanic corrosion. I would imagine that this boat was left in the water for a long time without anode refrash or use of the Mercathode system.

I never seen a case as the photo above, I myself experienced Galvanic Corrosion on my out drive after fresh gimbals and lower unit replacement I did myself on Alpha 1 drive. Mine started right after lake fresh water only testing.
I pulled my hair out trying to figure it all out! I have shore power- 30 amp hookup so this really complicates the issue.
Corrosion would happen to the out drive while on trailer if hooked up to battery charger, That's where I found that some grounding straps/clips on the exhaust bellows that continue the grounding circuit for isolation was installed improperly.

Regardless use anode anode anode anode, then maybe some more.. lol

Here is about how my dive looked only after one week in fresh water,

boat zincs site says...
Freshwater use magnesium anodes;

Install magnesium propeller nut anode.
​

 

[actros]

Re: Mercruiser 5.0L Advice required for flushing

Hi all,

Thanks for your reply and advice! I am looking forward now to buying my first boat, keeping it in the water and not worrying too much about corrosion!

Daniel