Re: Air in lower unit?
Vinney, in an attempt to start out at the beginning:<br /><br />Last week (Friday) I went to do my annual lower unit oil change on my 2001 Mercruiser 3.0L w/ Alpha 1 drive. I went and got it all done (yes, I filled it from the bottom to the top), and then decided to change the engine oil. I went to the closest slip (freshwater reservoir) and fired it up and was planning to drive it around to get the oil all nice and warm prior to changing it. Now, about two weeks prior, on a Saturday, one of the flush lines had popped off and was dumping raw water into the bilge. Only after it had filled the bilge up to the bottom of the engine had we realized what happened. I had opened the cowling to discover (and get sprayed with) water in the bilge. It was high enough for the serpentine belt to be slinging water on me. I quickly had my partner kill the engine and the bilge pump was already on, from before I went to pull the cowling.. better safe than sorry. About 10 mins later the water was gone, and we fired the engine back up and went on our merry way for about another few hours on the water and then back to the slip. It ran without a hitch. We also went out the next day and no problems at all. It has not been run since (About 2.5 - 3 weeks). This brings me to last Friday when I put it in the water at the reservoir. I fired it up (it was cranky, it had been sitting a while, so it took about 3 tries) and I noticed a weird noise/vibration. I thought maybe I was hearing things... maybe the old lube was just so thick and nasty it masked this noise before. Not the sort of noise you can hear where it is coming from, it seemed to reverbrate throughout the whole boat, sort of like a vibration. I thought maybe because it was on the trailer or something, so I backed it off, and floated there for a little while, but I still seemed to feel it. I did a few circles about 100' away from the dock, and at higher RPMs it seemed to be gone. Performance of the boat was on par with every other time I had her out. I brought it back in, and took it out of the water (for fear of damaging it). I doublechecked that there was oil in the drive (there was, the nice green color instead of black that I had drained out of it). Nevertheless, I went and changed the engine oil when I got back. Yesterday I went and hooked it up to the hose and ran it. Again, the noise in the boat. Outside the boat, nothing. Wheel side to side, no change in noise. At higher RPMs, it's not there. Now my dilemma - opinions are that it could be the gimbal bearing, or the u-joints, the thinking that the water might have gotten into the bellows from a vent inside the boat and removed the grease or something from the gimbal bearing. They say to remove the outdrive and check it out. I have a shop manual on the way, but I am anxious to get the problem resolved as soon as possible (I am a flyer in the USAF, and I could be flying out soon). I got a few other opinions from other sources, and one is that it could be the bendix on the starter. If the bendix is rusted it may be staying engaged to the flywheel. When the bilge filled the flywheel would have surely been forcing water into the starter motor.<br /><br />Basically, that's it! BTW - I was up in Wilmington, NC when VP Cheney was up there. We were on the C-17 that flew in the motorcade.<br /><br />--Chris
I will keep you posted.