Water in lower unit oil

[NWZFAN]

Help/advice needed.

Do any of you know if replacing the waterpump housing, seals, impeller, etc would fix water getting into the lower unit oil? I drained it, applied about 10-12 pounds of air pressure, but could not hear it leaking anywhere. Yet when I relaced with fresh oil, it was a milky tan color the next day after one fishing trip. Any help is greatly appreciated. I also posted anyother question regarding the fact that water comes up from my shift shaft area when reunning it in the driveway on a hose. Not sure if that is related.

The motor is a 1988 100hp Merc.
Ken

 

[Wingedwheel]

Re: Water in lower unit oil

It could possibly be the WP housing seals, the bushing seal on your shift-shaft or prop seals. Any of the three could allow water to integrate your LU.

 

[zorak]

Re: Water in lower unit oil

My Lu would hold the same pressure until i turned the drive shaft or rotated the shift shaft.I also submerged the LU in water and could see the bubbles when i would turn the shafts.I bought the LU seal kit but for now i only replaced the top seals in and around the water pump.I will do the prop shaft seals etc this winter.If you oil was milky before then yes it will be milky again unless you fix the seals.

 

[Moody Blue]

Re: Water in lower unit oil

Help/advice needed.

Do any of you know if replacing the waterpump housing, seals, impeller, etc would fix water getting into the lower unit oil? I drained it, applied about 10-12 pounds of air pressure, but could not hear it leaking anywhere. Ken

Possibly yes, possibly no. Water intrusion is possible by four places.

1) lower waterpump seals (driveshaft)
2) shift shaft bushing
3) prop shaft seals
4) fill and vent plug seals

You most likely will not hear air escaping as it would be a VERY small leak. Need to submerge the whole thing under water and watch for bubbles.

In some cases (depending on which seal may be defective) you would need to apply a vacuum instead of pressure to determine a leak.

 

[Mi duckdown]

Re: Water in lower unit oil

Yes. you have to do pressure and vacuum check. Don't have my manuals handy, so I don't the values. for each. (PSI)

 

[Wingedwheel]

Re: Water in lower unit oil

Possibly yes, possibly no. Water intrusion is possible by four places.

1) lower waterpump seals (driveshaft)
2) shift shaft bushing
3) prop shaft seals
4) fill and vent plug seals

You most likely will not hear air escaping as it would be a VERY small leak. Need to submerge the whole thing under water and watch for bubbles.

In some cases (depending on which seal may be defective) you would need to apply a vacuum instead of pressure to determine a leak.

Moody Blue is right, I fogot about the filler plug seals. DOH!