Engine flush

sogood

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May 11, 2016
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Apart from using muff, is there any other "access point" to flush my engine? I'm thinking specifically of using my freshwater holding tank to flush the engine, after its saltwater use. The tank would hold much more water ( about 60 litres) than I would normally use. I was thinking of plumbing in a spare line from the present sink supply. Any thoughts? 1990 5.7 Mercruiser V8 raw water cooled. Thanks in advance.
 

bruceb58

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Mar 5, 2006
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No way....60 liters is nothing! That would go through your engine in seconds.

You also couldn't do it unless you had a Bravo drive and the water was pressurized to allow enough flow.
 

alldodge

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Agree, another issue which could cause some problems for your impeller is the boats water pump can not supply water fast enough for the boat. City water pressure is minimum at best, the boats wouldn't stand a chance
 

tpenfield

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+1 . . . 60 litres might supply about 60 seconds worth of water, but that would not fully purge the engine block, because of the way in which water circulates (and re-circulates) through the engine.

Also would not really work with an Alpha drive, would only work with a Bravo drive as Bruce said.
 

sogood

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May 11, 2016
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Thanks for the prompt responses. So there's no effective way to flush the engine or even any crucial parts this way. I was thinking it might have been possible without the engine running, just to somehow run fresh water through it. As mentioned before, my boat will be moored, but at least it's in a tidal estuary, fed by a river, so on each return the engine will have run through brackish water to get to the mooring. That can only help somewhat. Thanks again.
 

bruceb58

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You might be able to run some water through the manifolds in addition to the slight flush you get by going up the river. You could also put some salt-away with it. You unlikely won't get any water through the engine as your thermostat will close almost immediately when the cold flush water hits it.
 

Scott Danforth

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Look up super flush. Specifically the SF-400

But you still need a garden hose
 

sogood

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May 11, 2016
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Forgot to mention that my fresh water is pumped, at a pretty solid rate. Last time I filled it and flushed it by running it empty, it ran for over 7 minutes. Will look at that SF400. thanks.
 

Scott Danforth

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Any flushing needs 15gpm or more flow rate.
 
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