Bought a rebuilt engine, exaust leak on bottom of manifold

[89Galaxy]

Is is possible to put the wrong manifold on a mercruiser? I took my boat to the shop and had a 2005 Rebuilt engine installed to replace the old 89 that finally bit the dust. I think they used all of my parts on this engine including the exaust manifold. The head has 6 bolts but the manifold only has 5.

It worked for about 10 hours before an exhaust leak in the bottom center occurred. There is NO hole in the old manifold gasket and i put a new one on it and it still leaked in the exact same spot. I did that TWICE before trying to use exhaust gasket sealer around both sides and letting it sit for 24 hours before i started it. Only let it idle and still leaking out of the bottom in the center below bolt 4 from the left side.

I sanded both surfaces and they seem smooth, I put a flat level on it and it appears flat...

I guess I just need to pony up the money for a new manifold? Because the engine is running great.. sat for 2 months started up on first key turn.. i let it idle for a little while.

 

[tpenfield]

:welcome:

You really need to find out if you have the right manifold for the rebuilt engine. Perhaps if you give us more details on the old & rebuilt engine, we can give you some more guidance. Since you have a mis-match in bolt patterns, it would be a good indication that the old manifold is not compatible with the rebuilt engine, but some details will help mail that down.

Got any serial numbers of the old & new engine and part numbers of the exhaust manifold?

 

[89Galaxy]

:welcome:

You really need to find out if you have the right manifold for the rebuilt engine. Perhaps if you give us more details on the old & rebuilt engine, we can give you some more guidance. Since you have a mis-match in bolt patterns, it would be a good indication that the old manifold is not compatible with the rebuilt engine, but some details will help mail that down.

Got any serial numbers of the old & new engine and part numbers of the exhaust manifold?

http://www.marineengine.com/parts/m...fold-and-water-system-use-w-1-piece-exh-elbow

If you look here, it shows that a 5 or 6 bolt manifold fits. OEM is 5 bolt. 6 bolt is the aftermarket.

Pretty sure its an OEM manifold.

The sticker on the head gasket cover shows OC478315 but I know for a fact the engine is not an 87-89 lol. I think that is just my old cover on the head gasket.

Im thinking it must be slightly warped and that is why its leaking because there is no cracks and the surface of both the exhaust manifold and head are smooth.

I looked on the head but wasnt able to find any numbers, I got this off the block: 14097080 - 159 - 04 : HECHOEN

If the head was warped it wouldnt be running great right? Starting easily and running great besides the exhaust leak.