Lower Unit Gear oil coming out water vent

[John R Williams]

I have a 99 Mercruiser 3.0 liter with an Alpha One out drive. I noticed a small amount of lower unit gear oil coming out of the top water vent holes of the lower unit. I checked the lower unit oil by draining a little gear oil out of the bottom drain plug and that oil did not have any water in it. My boat has a reserve tank that holds lower unit oil with a hose traveling through the transon into the outdrive. Any ideas on what this problem might be?

 

[nickster]

Re: Lower Unit Gear oil coming out water vent

John I would say that you do have a leak in your lower unit. It is probably in the water pump base and that is why you are not seeing any water in it yet, but over time there will be water in it and it could be very expensive to fix or even having to replace the entire unit. You need to get that unit resealed so you have a good and safe boating season.<br /><br />Good luck!<br />Nick