rylleeryllee
New member
"I started up my boat in the s
"I started up my boat in the spring and it started up fine. I have a 2005 4.3L Mercruiser. I put it in the water and boated for about 5-10 minutes and then it stalled. I opened up the hood and saw that there was milky oil coming out of the valve cover vents. I took the boat out of the water, drained the milky oil, ran new oil through it twice and then replaced the oil and the oil filter. I took the boat into a boat shop and they removed the intake manifold, saw a crack underneath and replaced it. They could not see any cracks in the block or heads. The boat shop indicated that there is a pocket in the manifold that water can remain in if the boat is sitting at a certain level. I started the boat and that's when I noticed it running rough and steam coming out of the one valve cover vent. The boat ran perfectly before it stalled in the water. When I take the plugs out, the engine turns over perfectly with no sounds or hydrolock. If I connect the ear-muffs and turn on the water with the plugs out, it still turns over perfectly. When I put the plugs back in and turn it over with the coil wire disconnected, after it turns over 2-3 times, it seems to experience hydrolock (sounds like it's sporadically undergoing load). I’ve taken out the plugs three times and turned over the engine to check for water, and no water comes out and the plugs are not wet. I’ve tested the compression and it’s 120 psi in all six cylinders. Your suggestions would be appreciated."
"I started up my boat in the spring and it started up fine. I have a 2005 4.3L Mercruiser. I put it in the water and boated for about 5-10 minutes and then it stalled. I opened up the hood and saw that there was milky oil coming out of the valve cover vents. I took the boat out of the water, drained the milky oil, ran new oil through it twice and then replaced the oil and the oil filter. I took the boat into a boat shop and they removed the intake manifold, saw a crack underneath and replaced it. They could not see any cracks in the block or heads. The boat shop indicated that there is a pocket in the manifold that water can remain in if the boat is sitting at a certain level. I started the boat and that's when I noticed it running rough and steam coming out of the one valve cover vent. The boat ran perfectly before it stalled in the water. When I take the plugs out, the engine turns over perfectly with no sounds or hydrolock. If I connect the ear-muffs and turn on the water with the plugs out, it still turns over perfectly. When I put the plugs back in and turn it over with the coil wire disconnected, after it turns over 2-3 times, it seems to experience hydrolock (sounds like it's sporadically undergoing load). I’ve taken out the plugs three times and turned over the engine to check for water, and no water comes out and the plugs are not wet. I’ve tested the compression and it’s 120 psi in all six cylinders. Your suggestions would be appreciated."