Damp exhaust manifold

[Deadonthewater]

When having my 93 mercruiser 7.4 winterized, the service tech said half a pint of water was pulled out of the oil pan. He advised I do a leak down test to insure the head gasket wasn't blown. I performed the leak down test and found less than 10% loss in all but one cylinder which showed 15% loss. So it appears the head gasket is okay. I pulled the starboard riser and manifold and found the exhaust side of the manifold was damp. Pulled the port side riser and it was bone dry. However, both exhaust flaps are completely gone. I then, with a little redneck ingenuity, pressurized the water side with 30psi air while filling the exhaust side with water on a bench. No bubbles, so no leak. So now I'm wondering if it was just a bad riser gasket? This has the stainless risers and they look like new. I did notice that the riser/manifold joint had two gasket stacked. Is this normal? Is it likely I just had a gasket leak? Is there another way water could have entered the exhaust from a standard winterization? Is there a good way to actually test the riser for leaks? Any advise is appreciated.

 

[Scott06]

i think normally best to test the manifold by filling with acetone that will wick into cracks easier. Other than that yes two gaskets would only be used if there was a block off plate in between for closed cooling. Would take all gasket material off and file it flat or use belt sander. If they are both flat and the wall is not eroded where gasket seals they should be ok.
is there any way water got in intake ? Would think if water was in there when running You would have milkshake not water separated from oil .