Lower Unit leaking from weep hole

B

Bob&Alicia

New member
The C-Dory has been in the driveway for several weeks now. I walked by it yesterday and noticed that lower unit oil was dripping out of the weep holes. This is new. If it had been doing it I would have noticed it on the driveway and it would have had a pollen clogged trail down the motor.

The only thing I can think of we have had some big weather changes. Not unusual for it to me high 30s night and 80 during the day. The boat gets the hot afternoon sun.

Is it possible that the temperature changes has caused some type of expansion?

The fluids looks clear. We have not noticed it leaking before. It has been weeks since the motor was run. It was in dry stack and I towed it home. Did not run the engine. I don't know what variable has changed other than the temperature. I was tempted to by an inexpensive pressure guage off Amazon and get a threaded fitting and tubing and follow the pressure recommendations in the service manual to check for a leak. If I had been running the motor I definitely would but it has just been sitting here.

Any thoughts?
 
when was the lower unit oil changed? Was it "over filled?

Drain the lower unit and check for water. Then you can pressure and vacuum test the seals. There will be the prop shaft seal--usually cut by fishing line on the propshaft.

The shifter seal, and engine shaft seal on the top, are more susceptible to wear, and increased pressure.

I doubt that the temp change caused a problem. We can have those temps here in N. Florida--and never had a problem with leaking.
 
Where is the leak? I havent see weep holes on lower units just 2 drains, drive shaft from OB and prop drive shaft.


Is the LU cracked? or leak from powerhead downstream to LU?
 
I had something similar happen to me last year. I kept the boat in the garage all winter and in between boat trips, so I would have noticed a leaking lower unit. Left for Lake Powell and spent a week in Ashland, OR at the Shakespeare festival. The boat was parked for a week in the same spot, with daytime temperatures in the mid-90's (unfit for man or dog) and I noticed about 5 drops of oil under the lower unit. Bought a really big screwdriver and checked tightness. Seemed okay. When I got home, I drained and there was no water in the oil. I have to think it was heat, but that's the go to guess.

Mark
 
BrentB":2e3g13jm said:
Where is the leak? I havent see weep holes on lower units just 2 drains, drive shaft from OB and prop drive shaft.


Is the LU cracked? or leak from powerhead downstream to LU?
Click to expand...

Brent the weep holes are generally below the water intakes on the side. They are there to allow the last little bit of water to drain out, and prevent freeze damage. They are above the lower unit--not vents for the lower unit. Leakage from around the shifter or power shaft seals will show up there.
 
I'm going to try and attach an image of the weep hole. I wipe the lower unit fluid off each night and it doesn't show up again until the late afternoon sun hits it.

We did have some freezing temps right after we brought the boat up from FL but the unit was tilted down and I wrapped a thick moving blanket over it. I have not had an outboard where it might freeze so wasn't sure what to do so it was easy to wrap it.

The marina service dept changed the lower unit fluid 100 hours ago. It is time for the 100 hr service. I have found a guy that works on outboards and I will get him to help me with the service. I will see if I can rig some type of pressure tester to test it. I have the service manual with the PSI specs. Harbor Freight or Autozone will probably have some type of tester. I can rig it to the fitting used for putting in the lower unit fluid.
 
Autozone has a radiator tester with gauge. Remove the cap adaptor, and with a small clamp on the rubber hose, you can attach to a fitting which screws in to the oil filler hole in the lower unit. I used the plastic fitting which comes with the pump for bulk filling of the lower unit. Carefully apply the specified pressure and submerge the unit in water. Bubbles will show if the seals on the prop shaft or upper seals on the drive shaft are bad. You cannot do a leak down vacuum test with this tool.
 
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