Lower Unit oil leak

[Klay4544]

1994 2-cycle carbureated150 yamaha. Had small amount of water in lower unit and boat would kill after start up. Boat not used past three months. Plugs were very black, so Installed new upper and lower unit seals and Shift Shaft seals. Attached lower unit and prop. One bolt next to the Anode bolt attachment was lost during repairs. Put in new lower unit oil and in 5 minutes oil starts dripping out under prop. Boat has not been started in 3 months. What could be the problem? If the seals were installed upside down could that cause the leak? I am at a loss right now

[fairdeal]

I doubt the seals would leak if installed "upside down".

But I can easily imagine, on a 27 year old motor,
that the case is corroded, and the o-rings on the propshaft bearing carrier
have nothing to seal against.

Who replaced the seals?
when the job was completed,
and a pressure test of the LU was performed,
what was the result?

[Jason2tpa]

I don't see how the motor kill and fouled spark plugs are related to the LU leak. The motor will start and continue to run if there wasn't oil in the LU...I know this from experience. So I'd approach this one system at a time. Tackle the LU issue then fuel/spark issue.

When you say LU oil leaking from under prop, where exactly is the oil coming from?...drain plug??