John E3
Active Member
I have another post about an engine mess that I found in the spring launch prep, but have a more targeted issue/question.
My issue was that both exhaust risers/elbows developed an internal water leak that allowed water to seep into the exhaust chamber, accumulate in the exhaust ports, and get into the cylinders. One head was so rotted that is not usable as a core. 50% of the port walls are gone. Cylinder 6 was completely full of water from the winter storage. This leakage has probably been going on for years. 5 cylinders showed signs of water intrusion in the past. A shortblock is in my near future. Depending on what I find in the stbd engine in the fall that future may be sooner, if that one is as bad. After doing just the top end in place (with ample room, mostly), removing the salon ceiling hatch, and yanking them out whole may be the better option as I can bring them to my shop and work inside all winter long.
Has anyone experienced this type of leakage? Is this a common thing? What can you do to ensure it does not happen again?
My 2nd engine may be in a similar state, but I'm putting that one off till fall so we can salvage at least half a season this year (our first season with this boat). Our lift operator is off this week, so another week delay, too.
Also, I decided to go with OEM exhaust parts, and Mercruiser has done away with the manifold drain plugs and the drain in the elbow. A paper came with it that says they are not required. I am a bit skeptical that you can drain the manifold and riser sufficiently to avoid freezing, with no drain plugs. The only other drain is the plug in the sea water pump outlet hose. It is below all the sea water passages, so I suppose just that would get most of it, but I don't see how the water can get out of the lowest parts of the manifold as they are below the point where the hose connects, and the water in the manifold has to go UP through the heat exchanger to get to the low drain plug. I'm just not seeing how it can properly drain and avoid freezing. Or, maybe Mercrusier expects you to fill it with antifreeze? I'd be more comfortable with them being empty over the winter. Pulling the hose would at least allow most of the water to get out.
When I pulled the plugs on the old manifold one chamber did not get mixed with enough antifreeze, even though I ran about double the volume needed, so even this makes me leery.
My issue was that both exhaust risers/elbows developed an internal water leak that allowed water to seep into the exhaust chamber, accumulate in the exhaust ports, and get into the cylinders. One head was so rotted that is not usable as a core. 50% of the port walls are gone. Cylinder 6 was completely full of water from the winter storage. This leakage has probably been going on for years. 5 cylinders showed signs of water intrusion in the past. A shortblock is in my near future. Depending on what I find in the stbd engine in the fall that future may be sooner, if that one is as bad. After doing just the top end in place (with ample room, mostly), removing the salon ceiling hatch, and yanking them out whole may be the better option as I can bring them to my shop and work inside all winter long.
Has anyone experienced this type of leakage? Is this a common thing? What can you do to ensure it does not happen again?
My 2nd engine may be in a similar state, but I'm putting that one off till fall so we can salvage at least half a season this year (our first season with this boat). Our lift operator is off this week, so another week delay, too.
Also, I decided to go with OEM exhaust parts, and Mercruiser has done away with the manifold drain plugs and the drain in the elbow. A paper came with it that says they are not required. I am a bit skeptical that you can drain the manifold and riser sufficiently to avoid freezing, with no drain plugs. The only other drain is the plug in the sea water pump outlet hose. It is below all the sea water passages, so I suppose just that would get most of it, but I don't see how the water can get out of the lowest parts of the manifold as they are below the point where the hose connects, and the water in the manifold has to go UP through the heat exchanger to get to the low drain plug. I'm just not seeing how it can properly drain and avoid freezing. Or, maybe Mercrusier expects you to fill it with antifreeze? I'd be more comfortable with them being empty over the winter. Pulling the hose would at least allow most of the water to get out.
When I pulled the plugs on the old manifold one chamber did not get mixed with enough antifreeze, even though I ran about double the volume needed, so even this makes me leery.
