Yellowbird911
Member
- Messages
- 34
- Reaction score
- 18
- Points
- 17
- Boat Make
- Yamaha
- Year
- 2007
- Boat Model
- SX
- Boat Length
- 21
I researched but found nothing like this. Am getting some water in the oil, not a lot as the volume does not increase at least that I can tell. Have drained and filled oil 3 times and then took boat out for a about 4 hours of running, which included taking the kids tubing so several engine start stops. Oil is milky again so clearly there is a problem. Pulled spark plugs and did a compression test. All cylinders are between 110-120 and spark plugs all look exactly the same. Unfortunately I didn't have my bore scope with me so I couldn't look into cylinders. When I first spun the motor over cylinder no.2, second one forward of the oil tank I did see a few drops of water blow out but again the spark plug for that cylinder looks exactly like the other three. So next I pulled the exhaust manifold as from research I expected to find a corrosion bridge from the water galley to the exhaust port which I did not. The gasket is clearly suspect but not completely blown out. Pictured is the exhaust port and manifold port of the no. 2 cylinder. You can clearly see that the port above the exhaust valves is cleaner where as the other cylinders have an even coat of carbon. The exhaust manifold it also cleaner indicating water or more likely steam is traveling down the port. My question is how much of a water leak at the exhaust port could cause water to back up in to the cylinder. When motor shuts down is there enough water trapped in the head that it can run back in to the cylinder from a leaking gasket. Will replace gasket and clean out the motor oil again to see if it fixes it but I am doubtful. Seems more likely there is a crack in the head but the compression test is ok and this engine, port side, makes 300 hundred more than the starboard and run perfectly. Any advice is welcome.