Exhaust manifold

[gshldon]

Hello all,

A quick question, i did the test for a leaking manifold, and i poored the acetone into the manifold and everything is ok and nothing coming out of the exhaust ports at all or any where else for that matter. Lucky me.

Here is the question when i had the manifold about half full of acetone i tipped it up so all the acetone would run the back of the manifold so i could tighten up the front cover plate, as i did that i had acetone come out of the rear exhaust port, but as i laid it more level it stopped and nothing has leaked from it since and it has been about an hour and no drop in the level of acetone.

Would that be normal if the front of the manifold was raised about 6inches off the ground with the rear of the manifold was on the floor.

Thanks in advance for your answers

 

[Glastron_V210]

Re: Exhaust manifold

Tell us more about your manifold. Is it set up for fresh water cooling, or raw water cooling?

If raw water, and the risers are connected (they must be by your description), then when you tiped it up the acetone ran up the riser, into the location where the dry exhaust and the raw water mix, then back to the rear most exhaust port. Totally normal.

If you have a fresh water cooled manifold, and you put the acetone into the manifold and not the riser, then the riser/manifold gasket is leaking, allowing acetone to pass to the risers, and the rest is the same as above.


Chay

 

[Bondo]

Re: Exhaust manifold

Ayuh,.... Acetone, like water, seeks it's own level,...
If you lift 1 end, it'll flow out the other...


Btw,...
It's Usually the gasket faces of both the manifold,+ riser that Fail.....

 

[gshldon]

Re: Exhaust manifold

thanks for the responses, it is a fresh water cooling system, and the reason i am checking for internal leaks is that i had 2 small cracks on the out side of the manifold and want to make sure it is not leaking into the exhaust port and into the engine.

Here is what i did:

hooked up the a hose to the rear end cap and poored the acetone into the house until it was full and let it sit there to see if the level went down and so far it has not went down. I forgot to put the gasket on the front capp so it was leaking out of there right away, so i lifted the front of the manifold to remove the cap and put the gasket on and tightened it down and then lowered back level with the rear.

When i lifted it up to remove the front plate and replace the gasket that is when the acetone poored out of the rear exhaust port, but once i leveled it off then it stopped leaking from the rear port.

The riser is on the rear of the manifold, and it is the starboard side of a merc 898 engine.

Thanks

 

[Bondo]

Re: Exhaust manifold

it is a fresh water cooling system, and the reason i am checking for internal leaks is that i had 2 small cracks on the out side of the manifold and want to make sure it is not leaking into the exhaust port and into the engine.

Are the manifolds on the Freshwater side, or the Raw water side,..??

 

[gshldon]

Re: Exhaust manifold

i am sorry i am lost as to what you are asking

 

[Bondo]

Re: Exhaust manifold

Ayuh,...
Freshwater cooling means it has a Heat Exchamger... With a Radiator Cap....

Raw water cooling is running what your In,...
And,...
Even with only my high school education, I know there's not much Saltwater in Minnesota....

Anyways,...
Are the risers still bolted to the manifolds,..?? If so,.. Pull 'em Off...

 

[gshldon]

Re: Exhaust manifold

oh sorry it is a raw water system, my mistake. And you are correct no salt water in mn. I just want to make sure i am good to go as long as water getting into the engine.

The risers are off i pulled it off before i removed the manifold.

 

[Bondo]

Re: Exhaust manifold

When i lifted it up to remove the front plate and replace the gasket that is when the acetone poored out of the rear exhaust port, but once i leveled it off then it stopped leaking from the rear port.

Ayuh,... It sounds like you need a new manifold....
There shouldn't be anything in the exhaust side but Air....

 

[gshldon]

Re: Exhaust manifold

i know nothing is suppose to be in the exhaust ports, it only happened when i raised the front of the riser up about 6-8 inches higher then the rear and that is when it leaked out, but after i had it level and even with the front a little higher then the rear there was nothing in the rear exhaust port, the manifold is still full of acetone and the level has not dropped and it is going on hour 2 of being filled with acetone, i am just wondering since the front was raised so much higher then the rear if that is what caused it to get into the rear exhaust port.

Thanks

 

[Glastron_V210]

Re: Exhaust manifold

Can I disagree and agree at the same time?

Refer to my first post now that we know you have a raw water cooled manifold, then confirm it as follows:

Remove the riser as bondo says. This will cost you a bit of work to get the old gasket off (Think sharp strong scraper) and a $10 gasket to replace it.

Cap off the manifold in and out ports.

Now fill the manifold up to the riser gasket area with the manifold levelish and see if the level drops. I still think when you tipped it up the acetone returned through the riser which is connected to both the raw water and the exhust ports.


Chay

 

[gshldon]

Re: Exhaust manifold

Thanks Chay,

I did have the riser off when i did the test and the manifold qas filled with almost a full gallon of eceton. It remained at the same level for over 2 hours and the level did not drop at all, so i just put it all back together and will be watching it very closely for the first few trips out on the lake.

I do think the the level of lift had something to do with the acetone coming out of the rear exhaust port, as soon as i dropped the front a little bit then it completely stopped and never did it again.

Thanks for all the input

Gary

Happy boating