Rust in risers

Keith7481

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Aug 21, 2005
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Hi All, when winterizing last fall, I pulled the brass drain plugs at the end of the riser and as they were draining, I noted that the port side (5.0GL) drained a bit slower than starboard. I stuck my pinky in there and could feel a bit of scale inside the riser at the bottom of the drain hole. Starboard side was pretty clean. I"m trailering my 1998 Vista in freshwater and have never had any over-heat problems at all. Any opinions as to whether I should pull the risers for inspection, or just keep on eye on my temp gauge?. I've owned it for 7 years now and have not made any repairs to these parts, so am not sure if they are the original risers/manifold. Thanks in advance.
 

tpenfield

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The rust scale will settle at the bottom of the riser/manifold. So, it is not unusual that you would get some sediment there. Draining them like you did is probably helpful. Unless you are seeing other cause for concerns, I'd leave them along for now.
 

Scott Danforth

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in addition to rust, you will probably find rocks, shells and small critters in there as they make their way thru the cooling system and settle in the block and manifold.

I used to pull the plugs and run the motor for a bit to help flush the manifold water jackets when I winterized. however your coming up on 20 years. it wouldnt be a bad idea to plan on an inspection at end of season (new riser gaskets will be required)
 

Keith7481

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Aug 21, 2005
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Thanks, so pull the plugs and start the engine and let the water just run into the bilge a bit? That sounds like a good flush idea. Will give that a shot and plan on having them removed end of the season. Thanks very much to you both..
 

Scott Danforth

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Dont run for more than say 20 seconds
 

QBhoy

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Change as per the recommendation if in sea water...or wait until you get big flakes of thin metal coming out the drain plug.....perhaps too late by then.
 

Scott Danforth

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Change as per the recommendation if in sea water...or wait until you get big flakes of thin metal coming out the drain plug.....perhaps too late by then.

OP is in fresh water, not salt. manifolds last 30+ years in fresh water
 

QBhoy

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Hi Scott,

With regards to the manifolds lasting 30+ years in fresh water....have to disagree with you on that one, as would many others in my boat yard. Perhaps the difference is the cold damp environment over the pond here ? My previous boat had them changed at least twice in less than this period.
I used to not fill with antifreeze during the winter and left the block and risers empty. Perhaps that's the difference.
I do now, to prevent such corrosion.
 

castaic piper

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Jan 1, 2010
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33
I have cleaned out several by soaking in evaporust I think WD40 makes a simular product. it might be worth a shot if they are not completly rotted out.
 

BRICH1260

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Jul 6, 2011
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1,342
Make sure you stick something like a screwdriver up into the hole to help break up any debris. On both the manifolds and the block.
 
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