Evinrude Lowere unit leak question

[huntleybill]

I was pressure testing this Evinrude lower unit and found that when I pumped pressurized air into the oil fill hole, I would get are coming out the hole in the water inlet area. I have attached a picture showing where the air is coming out.

I have never seen a leak in this area. Is this lower unit housing scrap?

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[frankr]

I don’t know. Is the water pump attached? If it is, the drive shaft seal probably is leaking (below the pump). That hole is the water pump inlet. If it is coming out that hole but not around the drive shaft, you got a problem.

[huntleybill]

Yes, the water pump is attached. When I pressurized the unit, I put dish soap on all the areas that have seals. Including the drive shaft seal. I say no bubbles around the drive shaft. Why do I get the feeling that this housing may becoming a desk lamp base?!

[frankr]

That certainly is unusual. If it isn’t coming out the drive shaft seal, there must be a hole or crack connecting the water pump inlet with the oil chamber. I guess you can’t see it bubbling out with the pump off??? It’s worth a second look anyway.

[fleetwin]

Perhaps the gasket between the upper seal housing bushing and gearcase is bad. Pressure testing without the impeller housing screwed down snuggly can lead to this problem…The pressure pushes the housing up and off the gasket, sometimes ripping it…
Unfortunately, a cracked or porous housing can cause this problem as well.
Tell us more about what work has been done to this gearcase. Did the gearcase have water in it prior to the work?
I just reread your post, you mention that there was no obvious leak around the driveshaft seal….Did you pressure test without the impeller housing screwed in place? If so, hopefully you just have a bad gasket underneath the upper seal/bushing housing which is allowing pressurized oil to pump into the water inlet galley underneath the housing….

[frankr]

quote fleetwin:

Perhaps the gasket between the upper seal housing bushing and gearcase is bad. Pressure testing without the impeller housing screwed down snuggly can lead to this problem…The pressure pushes the housing up and off the gasket, sometimes ripping it…
Unfortunately, a cracked or porous housing can cause this problem as well.
Tell us more about what work has been done to this gearcase. Did the gearcase have water in it prior to the work?
I just reread your post, you mention that there was no obvious leak around the driveshaft seal….Did you pressure test without the impeller housing screwed in place? If so, hopefully you just have a bad gasket underneath the upper seal/bushing housing which is allowing pressurized oil to pump into the water inlet galley underneath the housing….

Oh. I guess I just jumped to the conclusion that this was the 35hp previously under discussion. But we are instead talking about a 5.5/7.5hp motor? What fleetwin says makes sense.

[raglover]

I have had three big twin 35 cases cracked on the front side of the water inlet cavity. All were 1958 super quiet style motors. Two johnsons one Evinrude. Cannot speak for the smaller motors as I have never seen it on them. I came to the unscientific conclusion that 1958 big twin gear cases have a weak spot. None of my 57’s or later 59’s have had this.

I was able to find it with soapy water spray.

Hope it is just the gasket if it is a small hp.

[huntleybill]

Sorry Frank. I have several outboards I am working on. This lower unit is out of a 1958 7.5HP motor.

[garry-in-michigan]

Hope this helps. Check 300599 seal. . . 🙂

[fleetwin]

The gasket in question is #41. It is possible that this gasket got damaged allowing the oil in the gearcase to escape into the water channel without seeing an external leak around the outside of the impeller housing while using the pressure tester.
Again, this problem can occur if you pressure test without the impeller housing screwed down securely, The pressure pushed the housing upwards and rips the gasket…

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