72 evinrude lower unit leak

[jaybirdbadger]

I have a 72 evinrude 18 hp motor that just started to leak oil from the lower unit. The problem is that the oil is coming from 2 small "holes" on either side of the check screw. What are these "holes", and what can I do to stop the leak? Any info would be greatly appreciated, this motor is running to good for me to screw it up.

 

[larky]

Re: 72 evinrude lower unit leak

I have no experience with your motor, but it sounds like you are describing the lower unit drain holes. they are there to completely drain the leg of water so that it won't freeze in the winter time and crack the lower unit housing. now, the leg is also the exhuast, so you are probably seeing some un-burnt fuel/oil coming out of those drain holes. hopefully some one with more first hand experience with your outboard will be along soon.

 

[Vic.S]

Re: 72 evinrude lower unit leak

If this oil is black and gungy it is as Larky says just partly bunt oil from the fuel and is normal.

If however this is clean gear oil it is coming from the gearcase, and water will almost certainly be leaking in. I can't picture where these two holes are exactly but I would suspect the drive shaft seals or possibly the O ring seal on the shift rod.

If it is gear oil and there are signs of water ingress (the oil going milky) you should have the unit vacuum and pressure tested to pinpoint the leakage. Or simply replace all the seals, propshaft seals as well. Renew the pump impeller at the same time.

 

[Vic.S]

Re: 72 evinrude lower unit leak

See also : http://forums.iboats.com/showthread.php?t=207285 in the Engine FAQs

 

[jaybirdbadger]

Re: 72 evinrude lower unit leak

Larky and Vic.S thanks so much for the reply. One more question. The oil is somewhat milky looking. Am I at risk of ruining something if I use the motor for short trips (15 min run time every couple of weeks) until fall when work schedule would allow me to take it apart and replace all the seals? Thanks again.

 

[Vic.S]

Re: 72 evinrude lower unit leak

Why not change the oil and see how it goes, but fit new seals to the level and drain plugs. I would not worry too much if you are running in fresh water, but would not want to leave it too long in salt water. You can always change the oil periodically if necessary though.

 

[jaybirdbadger]

Re: 72 evinrude lower unit leak

Vic.S thanks again for your input. I have already changed the oil, it looked fine but I plan on doing it often anyway. I really appreciate your help. I will be looking for a manual for my motor so I can start to prepare for what I'm sure will be a pretty tough challenge for me. Thanks again. Jaybird

 

[wilde1j]

Re: 72 evinrude lower unit leak

If the gear oil was not milky and there was no sign of water, it's not necessary to "change it often". Once a year, in the fall, will do just fine.