Mercruiser Alpha Gen 1 Lower Unit Hole

[NeelP]

First time poster. Does anyone know if the holes highlighted in the pictures are supposed to be there and what they do?
If they are not suppoed to be there, can they be filled in with an alum epoxy or the like?
Thanks

 

[NeelP]

Here is another brand lower unit with the same hole from Google images...

 

[Baylinerchuck]

My Alpha 1 Gen 1 has no such hole, on either side. How deep is that hole? Marine-Tex is what I would use to fill it.

 

[Creager_09]

Same problem with my My Alpha 1 Gen 1, it has two holes UPSers

 

[Scott Danforth]

those are cavity drain holes

 

[Rick Stephens]

⇧⇧⇧

Allows those cavities to drain so they don't freeze and crack or grow nasties and plug up.

 

[Baylinerchuck]

those are cavity drain holes

Was this something eliminated on later model Alpha 1 Gen 1’s? My Alpha was right as they made the switch to Gen 2. Mine has a single drain hole above the front of the prop shaft in line with the shift shaft. Just curious what cavity those holes would drain in that drive that mines not draining, let alone one on either side? :noidea:

 

[Baylinerchuck]

⇧⇧⇧

Allows those cavities to drain so they don't freeze and crack or grow nasties and plug up.

Also curious that those holes are not really opposite each other. One is higher, one is more aft. The pics aren’t really clear due to the resolution. As a drain hole they seem pretty high in the casting. Wondering if this is just corrosion.

 

[Rick Stephens]

Also curious that those holes are not really opposite each other. One is higher, one is more aft. The pics aren’t really clear due to the resolution. As a drain hole they seem pretty high in the casting. Wondering if this is just corrosion.

Well, with the paint all gone.......

I would not worry about a hole that doesn't leak oil. There are water passageways all over inside Merc drives. I always wondered why later model drain holes are so small and easy to plug with a couple grains of sand.

 

[NeelP]

UPDATE:
I have sold the boat so have not been able to physically inspect or get better pictures.
The photo of the port side 'hole' is some old paint. My apologies for assuming it was ahole.

The starboard side hole goes into the cavity. No oil or hitting anything when sticking a thin screwdriver in there.

Have also checked a later model Mercury outboard and there is a hole on the starboard side at the same height, just further to the back of the casing.

Tending to agree with Rick Stephens, that it is a drainage/vent hole to avoid cold or wet related issues.