Took off my lower unit to replace the impeller and do water pump service, and when I separated the lower unit, there was quite a bit of gear oil on the drive shaft in/around the spine where the drive shaft inserts into. Easily a couple tablespoons maybe more. It dripped out when I separated the lower and upper unit. The oil was very clean. This boat hadn't had it's gear oil changed in a long time- the gear oil I drained from the gear case was black. This oil however was green/clear - I think it matches the oil that had been in the reservoir in the engine compartment. I'm assuming it's gear oil anyway. My lower unit wasn't leaking as far as I could tell, nothing on my driveway and my boat had been there 6 weeks. Is this normal or does it mean I need to replace the upper seal or bring to a mechanic to service the upper unit? I just got this boat and this the first time I've worked on a mercury alpha one. I did notice that the reservoir was not full when I got it- I filled it but it's held level since I did. Granted I haven't had it in the water yet- just running on muffs for 10 minutes or so. There is a seal I assume I can see up there around the spline receiver where the shaft goes- that looks easy to replace- would that be the source of the leak or is it more likely a leak up way inside the upper unit? Is there any easy test I can do like just refill the reservoir, plug hole where the quad seal gasket would normally go with my finger and see if oil drips from up there? I have a vacuum/pressure hand pump gear case tester- could I just pressurize or vacuum test the upper unit using the vent hole- if so what PSI should I pressure or put vacuum on?
