Drain Exhaust Manifolds Black Water?

[34 ford]

1988 Bayliner 350Gm Omc outdrive.
Just drained the exhaust manifolds on my engine for winter, and the water was cold black, that drained out.
I have replaced the exhaust manifolds and risers this summer and ran the boat 1 time in July and it has not
been run since, that time.
Is the cold black water a concern?

 

[Boomyal]

Re: Drain Exhaust Manifolds Black Water?

.....Is the cold black water a concern?

No, it is normal. The black is nothing but rust off of the cast iron. Ideally, it would be best if it never occurred but it is the nature of the beast when raw water is left to sit in them for any period of time. I have mine set up so that when I drain them for winter, I can easily fill them with antifreeze. Easy as it is, it would be a pain to do it every time you used the boat.

It would be nice to design a system whereby you could pump a metered amount of undiluted antifreeze into them after every use. You'd never see the black water if that were done.

 

[Lou C]

Re: Drain Exhaust Manifolds Black Water?

Actually Volvo has their Neutra Salt system that flushes them with a solution that neutralizes the effects of salt ( not for freeze protection though). I hear it works well. My manifolds also have the dark dirty looking water as well; I fill em with -100 no tox AF for winterizing.

 

[34 ford]

Re: Drain Exhaust Manifolds Black Water?

Thanks! for answering my question. Guys.

 

[jerryjerry05]

Re: Drain Exhaust Manifolds Black Water?

Nothing to worry about.Stagnant water.
It's important to flush salt water out of the system.(profile,location?0)
During winter,just draining isin't really good for the systems.(a lot better than not!!
The block and manifolds exposed to the air will rust/corrode faster.
The other have good suggestions,any Marine antifreeze will work.
Regular automotive is illegal to introduce into any body of water.
I run the motor on the flusher and open the drains and push a piece of wire/small screwey in the holes.
THEN do the regular drain/fill.
Make sure the plugs and petcocks are closed if not filling with antifreeze.
They will be hard to put back in in the spring.

 

[34 ford]

Re: Drain Exhaust Manifolds Black Water?

Thanks Again for the answer.

 

[Lou C]

Re: Drain Exhaust Manifolds Black Water?

After manually draining including poking the drain holes to free rust, I back fill with -100 marine no tox antifreeze. It does cut down on corrosion. I also put OMC gasket sealer on the drain plugs and they always come out and don't leak salt water on the starter solenoid (why I started doing that, LOL...rusted up the terminals into a ball 'o rust)....

 

[500dollar744ti]

Re: Drain Exhaust Manifolds Black Water?

Just don't drink it.