I'll start at the beginning with this in hope is provides additional content to my issue. At the start of boating season last year I changed the water pump housing and impeller, reinstalled and filled with gear oil. I noticed that when I filled the oil it only took about 3/4 of a litre of oil before it started coming out of the air vent in the upper unit. I thought that was odd so I moved to more level ground (My driveway is on a decent slope), trimmed down all the way and tried to add more oil, but after one pump it was coming out of the vent again. Just thought maybe I did not get it fully drained and went boating. The boat ran fine all summer, we live on a lake so we use it pretty much every other weekend. On Labor Day weekend after pulling tubers for a few hours on the way back to the dock I heard a grinding sound, the motor stalled and when I tried to start back up again the sound was still there, so I paddled back to the dock. Since it was the end of boating season, I pulled the boat and left it to work on in early spring.
I found that that the upper unit gears failed due to lack of oil, so apparently I had an unnoticed oil leak and the upper unit and the gears finally gave out. I drained the oil, there was still about a half quart in the lower unit, and pulled the outdrive. I did not notice any water or metal filings in the oil when I drained.
Fast forward to this spring. I bought a used, but pressure tested, upper unit. I did all the maintenance that comes with pulling the outdrive (greased joints, replaced gimbal bearing, checked alignment, replaced water pump and all the gaskets and o-rings in-between, filled with new gear oil). Reinstalled and planned to put the muffs on and test the next day. However, when I came out the next day there was a pool of gear on the ground and a small oil leak coming out of the lower unit at the weep hole on the lower front end. I then drained the oiled and pulled the lower unit again. It looked like all of the oil residue was around the front end of the water pump and shift shaft and I did not notice anything on the upper part of the shaft. I went ahead and replaced the water pump base, o-ring, gaskets and shift shaft bushing/seals/o-rings, reinstalled filled with oil and the next day still had a leak in the same spot, but a little less. I thought maybe it was just residual oil, so I went ahead and tested with the muffs for about 15 minutes. Everything ran fine so I went away and mowed the yard, but when I came back there was oil dripping out again.
So drained the oil again, no water or metal shavings in the oil, and pressure tested last night. The upper unit held 15.6 psi for over 2 hours before I had to stop due to a storm coming (I did test the upper while still installed to the boat, so not sure if that makes a difference). I then pressure tested the lower unit and let it sit overnight and it held 15.3 psi for over 7 hours. I also turned the shaft and prop while testing to see if that would cause any pressure loss, but it did not.
Any suggestions of what to check now? The engine is a MerCruiser 4.3L 175HP, the outdrive is an Alpha 1 Gen 1 and the boat is a 1988 Sea Ray Seville.
I found that that the upper unit gears failed due to lack of oil, so apparently I had an unnoticed oil leak and the upper unit and the gears finally gave out. I drained the oil, there was still about a half quart in the lower unit, and pulled the outdrive. I did not notice any water or metal filings in the oil when I drained.
Fast forward to this spring. I bought a used, but pressure tested, upper unit. I did all the maintenance that comes with pulling the outdrive (greased joints, replaced gimbal bearing, checked alignment, replaced water pump and all the gaskets and o-rings in-between, filled with new gear oil). Reinstalled and planned to put the muffs on and test the next day. However, when I came out the next day there was a pool of gear on the ground and a small oil leak coming out of the lower unit at the weep hole on the lower front end. I then drained the oiled and pulled the lower unit again. It looked like all of the oil residue was around the front end of the water pump and shift shaft and I did not notice anything on the upper part of the shaft. I went ahead and replaced the water pump base, o-ring, gaskets and shift shaft bushing/seals/o-rings, reinstalled filled with oil and the next day still had a leak in the same spot, but a little less. I thought maybe it was just residual oil, so I went ahead and tested with the muffs for about 15 minutes. Everything ran fine so I went away and mowed the yard, but when I came back there was oil dripping out again.
So drained the oil again, no water or metal shavings in the oil, and pressure tested last night. The upper unit held 15.6 psi for over 2 hours before I had to stop due to a storm coming (I did test the upper while still installed to the boat, so not sure if that makes a difference). I then pressure tested the lower unit and let it sit overnight and it held 15.3 psi for over 7 hours. I also turned the shaft and prop while testing to see if that would cause any pressure loss, but it did not.
Any suggestions of what to check now? The engine is a MerCruiser 4.3L 175HP, the outdrive is an Alpha 1 Gen 1 and the boat is a 1988 Sea Ray Seville.
