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Oil leaking from hole

L

last_dollar

Member
I have a 1986 4.3 Mercruiser w

I have a 1986 4.3 Mercruiser with an Alpha One drive. What appears to be lower unit oil leaks from a vent hole in the lower part of the outdrive just below the prop shaft level. Is this normal? It has never done this before. What can cause it?
 
"No, it is not the drain plug

"No, it is not the drain plug screw. This hole is on the opposite side of the housing. It is 1/8 inch in diameter and open. It looks like it is there for a purpose, I have seen these holes in lower units before. This is the first time I have experienced oil coming out of this hole, it appears and smells like lower unit oil."
 
that hole is a drain. the oil

that hole is a drain. the oil most likely is leaking from the shift shaft seal in the lower. sounds like time for a reseal. any water in the oil?}
 
"Wrong...

The oil screw you

"Wrong...

The oil screw you are referring to is the VENT screw. This is the screw you should remove while filling the lower unit with oil. Once the oil trickles out its full. As berry said, it has a rubber o ring. This is probably your issue. Replace the o ring and let us all know."
 
"Dave... wrong again. The vent

"Dave... wrong again. The vent screw is on the upper unit. The hole described above is on the lower unit, 'below the prop shaft level'... I don't recall any holes as such on my lower unit. I'll take a look at it tonight."
 
"That little Hole is to drain

"That little Hole is to drain the cavity Around the Oil cavity,.....

scott stephens has it Nailed,......

Usually when Oil appears there,.... It's the Shift-Shaft that's Leaking........"
 
Soon as good weather arrives I

Soon as good weather arrives I'm pulling the lower unit off at the water pump level and will probably find that it is the shift shaft seal.
I'll respond back when I find out. Thanks to everyone!
 
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