Can someone tell me what this is?

[MTboatguy]

It looks to be some type of vent on the lower unit, but none of the diagrams I have looked at note this small hole in the lower unit above the mating point of the gear case. The reason I ask, is because I fired and ran the motor in a tank yesterday, shifted gears, showed no problems, I then parked the boat with the motor in the travel position and when I checked this morning, I noticed a trickle of oil from this hole, I wiped it off and no more has trickled out.

Thanks, I sure will be glad when my service manual arrives.

'61, big twin 40.

 

[a70eliminator]

Re: Can someone tell me what this is?

Nothing to worry about and completely normal for oil to ooze from the hole, it's just a drain from the exhaust housing where unburnt oil accumilates.

 

[Vic.S]

Re: Can someone tell me what this is?

I suspect just a drain hole.

Was the oil unburnt or partly burnt oil from the fuel. If so no problems.
If it was gear oil then you have seal leaking. Have you checked the gear oil for signs of water ingress ... milkiness?

Other people type faster than me !

 

[MTboatguy]

Re: Can someone tell me what this is?

Thanks guys,

I figured as much, the lower unit has just been completely rebuilt by me and I pressure checked it for leaks, none present. The small amount of oil that trickled was not milky and it was darker than the gear oil...

Thanks again.

Dave

 

[F_R]

Re: Can someone tell me what this is?

You ran it in a tank. Remember all the oil slick and scum that accumulated in the tank? That is what is running out the drain hole.

There will also be some draining out even after running it on a boat. The oil that you put in the gas goes out the exhaust. That hole drans a low point in the exhaust area.