lower unit seal leak

[jerry place]

i'v e got a 88 mercury 100hp that i recently bought. problem i'm having is i am getting water in my lower unit gear oil. it's not a lot but it's enough to turn the oil milky white in one trip. i've replaced the impeller, impeller housing seal, base gasket, the two rubber seals under the water pump base and the shift shaft seals. my question is where else can water be getting in? i'm thinking the prop shaft side? are the seals in there as easy to get to as the impeller side?
thanks, this forum has been a lot of help.

jerry

 

[achris]

Re: lower unit seal leak

The best way to find a water ingress point if with a vacuum gauge. The prop seals and relatively easy to replace, if you have the right tools. It can be done with the bearing carrier in place, but it is way harder. the easiest way it to remove the bearing carrier cover and the bearing carrier, then replace the shaft seals AND the carrier 'o' ring. The only other area you may have missed is the fill and vent plug washers.

Chris.......

 

[jerry place]

Re: lower unit seal leak

thanks for your reply. i don't remember seeing any washers on the vent and drain plugs. are they for sure supposed to be there?

 

[achris]

Re: lower unit seal leak

Parts numbered #5 are listed as , "Washer - sealing", part number is 12-19183.

Chris...........