Fishermark
Vice Admiral
- Joined
- Oct 19, 2003
- Messages
- 5,617
Sorry about the long post but I have several questions.<br /><br />I took the boat out Saturday, (24' Sportcraft walk around, 5.7 liter Mercruiser, alpha 1, gen 1), was enjoying a leisurely cruise, about 3,000 rpms, about 3 miles offshore when it felt like we hit something. (I don't think we did, it just felt like it). The engine ran fine, but the outdrive wouldn't go back into gear - either forward or reverse. Got towed back in (Membership in Seatow is a wonderful thing!! 
).<br /><br />At the house I took out the lower plug and milky oil came out. <br /><br />Took off the top cover and was able to pull the top of the drive shaft completely out. It had snapped off clean right at the top of the driven gear. (That can't be a good thing, right? )<br /><br />Questions:<br />1) First, regarding the water in the oil. I recently replaced the water pump on this outdrive. When I drained the oil to separate the lower unit from the upper, the oil was fine - no evidence of water. (I had the outdrive resealed last summer). After putting in a new water pump kit I reassembled the lower unit with a new quad ring (o-ring). The only thing that makes sense is that I must have knocked the quad ring out somehow during reassembly. I realize this is a little late now, but I plan on pressure testing the outdrive every time I do any kind of work on it from now on. Is there a fitting you can buy to do this with an air compressor? Is 15 pounds the right amount of pressure to use? Is it necessary or common to vacuum AND pressure test the unit?<br /><br />2) A related question regarding the water in the oil. I am assuming the broken drive shaft is a result of the water in the oil - something must have frozen up due to lack of proper lubrication. But when I removed the top cover I noticed the the level wasn't down, and I only had maybe three hours of operation after replacing the water pump. Is it possible that the broken drive shaft occured from something else? In other words, when it broke, maybe it broke something else internally which broke into the water jacket and caused a mix of the water and oil?<br /><br />3) I realize this may be a hard question to answer, but is there a "typical" amount of damage that occurs when this happens? Will I luck out and only need to replace the drive shaft typically? Or does it shred everything else inside? (Ironically enough, when I removed the top, the teeth on the drive gear look perfect. In fact the driveshaft popped cleanly in two - almost like it was cut with a saw.<br /><br />I don't plan on doing this repair myself, but I would like to have an idea of what I am looking at before the tech tears into it.
).<br /><br />At the house I took out the lower plug and milky oil came out. <br /><br />Took off the top cover and was able to pull the top of the drive shaft completely out. It had snapped off clean right at the top of the driven gear. (That can't be a good thing, right? )<br /><br />Questions:<br />1) First, regarding the water in the oil. I recently replaced the water pump on this outdrive. When I drained the oil to separate the lower unit from the upper, the oil was fine - no evidence of water. (I had the outdrive resealed last summer). After putting in a new water pump kit I reassembled the lower unit with a new quad ring (o-ring). The only thing that makes sense is that I must have knocked the quad ring out somehow during reassembly. I realize this is a little late now, but I plan on pressure testing the outdrive every time I do any kind of work on it from now on. Is there a fitting you can buy to do this with an air compressor? Is 15 pounds the right amount of pressure to use? Is it necessary or common to vacuum AND pressure test the unit?<br /><br />2) A related question regarding the water in the oil. I am assuming the broken drive shaft is a result of the water in the oil - something must have frozen up due to lack of proper lubrication. But when I removed the top cover I noticed the the level wasn't down, and I only had maybe three hours of operation after replacing the water pump. Is it possible that the broken drive shaft occured from something else? In other words, when it broke, maybe it broke something else internally which broke into the water jacket and caused a mix of the water and oil?<br /><br />3) I realize this may be a hard question to answer, but is there a "typical" amount of damage that occurs when this happens? Will I luck out and only need to replace the drive shaft typically? Or does it shred everything else inside? (Ironically enough, when I removed the top, the teeth on the drive gear look perfect. In fact the driveshaft popped cleanly in two - almost like it was cut with a saw.<br /><br />I don't plan on doing this repair myself, but I would like to have an idea of what I am looking at before the tech tears into it.
