Oil in water vent.

[Bone08m]

After I pulled the boat out of the water I noticed that there is a small amount of oil leaking from the water vent. I checked the gear oil and it is milky. When i unscrewed the plug there was some water that came out first. Does this indicate bad seals in the lower unit? The motor is a 1979 55hp Evinrude. Any help would be greatly appreciated.

 

[OBJ]

Re: Oil in water vent.

Welcome to iboats Pike!<br /><br />Yea....something is amiss somewhere. Could be the prop shaft seals (2), drive shaft seals (2), shift rod oring or bearing carrier oring.<br /><br />What is generally done is a pressure test is done on the lower unit. This is done by draining all the gear lube out and applying about 15psi air pressure. Easy to do with a bicycle pump and adaptor for the drain or vent plug hole. Once the press is applied, dump the whole shebang in water and look for bubbles.<br /><br />If you fish a lot, pull the prop and look for fishing line around the prop shaft in back of the prop. Nylon fishing line can destroy seals quickly.<br /><br />You can also just re-seal the whole lower unit and cover all the bases. But a pressure and vacuum test is still a good thing to do once the lower unit is back together.<br /><br />About the oil from the vent hole, is that the little hole near the front of the lower unit?

 

[Bone08m]

Re: Oil in water vent.

Thanks OBJ.<br /><br />The vent hole I meant is the water intake screens. <br />I have removed the prop. There was no fishing line but the seal on the inside of the prop itself is split on the inside. Does this seem likely that this is the source of the intrusion.

 

[OBJ]

Re: Oil in water vent.

The prop shaft seals are located in the bearing carrier....that's the assembly in back of the prop in the lower unit. The prop doesn't have any seals.