496 Mag risers
05-07-2016, 07:36 PM
#1
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496 Mag risers
Last month I pulled my risers on my '07 496 Mag and inspected the manifolds for corrosion. Reinstalled everything with new gaskets after seeing no issues. Took the boat out today and my port side riser is leaking water. It appears to be leaking around the joint with the manifold. How can that be? It's a dry joint. Could it just be a hose leak but just appears like it's the joint?? What am I missing here?!?
05-07-2016, 08:20 PM
#2
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So it's not leaking where the riser bolts to manifold. Gasket didn't get flipped around or assbackwards or anything like that? Sounds like what your saying is almost like a manifold crack. Do u have a paid membership? If so post a pic and it will be much easier to determine what's going on.
05-07-2016, 08:26 PM
#3
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it looks like it's leaking around the gasket at the joint between the riser & manifold. There were no issues with leaks last Fall. I only took everything apart to inspect for corrosion since the boat is on year 9. Didn't see a bit of corrosion. But since it's a dry joint, I'm stumped. Tomorrow going to have to tear into it again.
05-07-2016, 09:18 PM
#4
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I don't get it. Your saying its a dry surface meaning no water jackets that transfer water from the manifolds to the risers. Of course it can leak if you don't have a good seal. Their both machined surfaces and if clean and free of debris etc they should leak. When you pull riser back off ck surfaces with a straight edge and maybe use a sanding block lightly with some 320 on both surfaces. Thin layer of silicone on each might not hurt when bolting back up. Salt water or fresh water manifolds?
05-07-2016, 09:45 PM
#5
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its a DRY JOINT exhaust manifold and riser from OEM stock Merc. They did this to all black engines starting in 2002 . 2003 timeframe.
SORRY MY BAD TOTALLY AT FIRST AS I THOUGHT IT WAS AN EXHAUST LEAK but is a WATER LEAK. Wrote for an exhaust leak but all changed now
the fitting in the exhaust manifold could be your leak source. The ones that your hose end connects to - manifold side, these are pressed in - possible lost its seal or its cracked or not set in correctly .
next info - Check your hose that the hose clamp did not pinch thru the hose causing the water leak and check the hose clamps for tightness. Lastly check make sure the hose does not have small hole in it possible making you think its leaking at the gasket.only.
next as only thing left - Possible crack in the manifold - pressure test it
SORRY MY BAD TOTALLY AT FIRST AS I THOUGHT IT WAS AN EXHAUST LEAK but is a WATER LEAK. Wrote for an exhaust leak but all changed now
the fitting in the exhaust manifold could be your leak source. The ones that your hose end connects to - manifold side, these are pressed in - possible lost its seal or its cracked or not set in correctly .
next info - Check your hose that the hose clamp did not pinch thru the hose causing the water leak and check the hose clamps for tightness. Lastly check make sure the hose does not have small hole in it possible making you think its leaking at the gasket.only.
next as only thing left - Possible crack in the manifold - pressure test it
Last edited by BUP; 05-07-2016 at 11:10 PM.
05-07-2016, 11:19 PM
#7
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its a DRY JOINT exhaust manifold and riser from OEM stock Merc. They did this to all black engines starting in 2002 . 2003 timeframe.
SORRY MY BAD TOTALLY AT FIRST AS I THOUGHT IT WAS AN EXHAUST LEAK but is a WATER LEAK. Wrote for an exhaust leak but all changed now
the fitting in the exhaust manifold could be your leak source. The ones that your hose end connects to manifold side . Check your hose that the hose clamp did not pinch thru the hose causing the water leak and check the hose clamps for tightness. Lastly check make sure the hose does not have small hole in it possible making you think its leaking at the gasket.only.
next - Possible crack in the manifold - pressure test it
SORRY MY BAD TOTALLY AT FIRST AS I THOUGHT IT WAS AN EXHAUST LEAK but is a WATER LEAK. Wrote for an exhaust leak but all changed now
the fitting in the exhaust manifold could be your leak source. The ones that your hose end connects to manifold side . Check your hose that the hose clamp did not pinch thru the hose causing the water leak and check the hose clamps for tightness. Lastly check make sure the hose does not have small hole in it possible making you think its leaking at the gasket.only.
next - Possible crack in the manifold - pressure test it
05-08-2016, 07:33 PM
#10
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well, I found that the hose clamp at the manifold was loose. Pulled the hose, inspected the bibs and found no holes or cracks. Reinstalled and I also loosened up the Corsa diverter and the pipe to make sure that wasn't putting pressure on the riser. Retightened everything and ran in the driveway up to temperature and ran it at 1200 RPM for a few. No more visible leaks. So next week I'll put it back in the water and hope all is good.
