Prop shaft seal replacement?

[craigman]

Fellas,
boating season is here and getting my boat ready to go.
Problem is that I have water in my lower end. Thinking I need to reseal the propshaft and water pump area.
How hard is it to replace the seals in the lower end? And a good place to buy the seal kit?
It's a 74' Merc 850. (85hp)
Thanks for any help!

 

[aussieflash]

Re: Prop shaft seal replacement?

Dont forget the Fill and vent plug seals/washers.Sometimes they are the culprit.Use the correct nylon style.Refill and take for a run,then re check oil.It could be your easiest fix.When you re check just let a bit of oil out the drain plug as water will be the first out.

 

[craigman]

Re: Prop shaft seal replacement?

You know, I never thought of that. I don't believe there is any seals on the fill or vent plugs. Last time I changed the oil I noticed plug were SUPER tight.
I'll definately check that first!
Thanks!

 

[Texasmark]

Re: Prop shaft seal replacement?

You know, I never thought of that. I don't believe there is any seals on the fill or vent plugs. Last time I changed the oil I noticed plug were SUPER tight.
I'll definately check that first!
Thanks!

These seals are special and the ones I use are light blue in color and fiberous, not metallic. I understand that there are new ones out that are yellow and are a silicon seal in a metallic ring.....but you MUST have a seal on EACH of the SS screws in the LU where the oil is held.

If your prop shaft is leaking, you will see oil around the seal and the shaft when it is obvious that the oil didn't come from exhaust left overs. I have changed out seals on engines of that size and did it by carefully removing the seal by picking it out, possibly drilling small holes in it so that I could stick something in the hole to pull it out, collapsing the outer part of it with a small punch or screwdriver and hammer...... Not that big of a job, just time consuming.

Mark

 

[craigman]

Re: Prop shaft seal replacement?

Thanks for the info Mark!
I'll look at it today and double check on the seals. I hope that's my problem!

 

[Mi duckdown]

Re: Prop shaft seal replacement?

Also check when you have the fill and vent plugs out, that there is Not part of the OLD washers stuck to the lowerend housing.
Use a pic or small screwdiver to inspect. the older ones were black and hard to see when fused to the housing.

 

[Moody Blue]

Re: Prop shaft seal replacement?

Before going through the trouble and expense of replacing ALL the seals, do a pressure test to determine exactly where the leak is occurring and then fix that particular seal(s). The old adage "if it ain't broke don't fix it" applies here.

 

[craigman]

Re: Prop shaft seal replacement?

Ya I was thinking of pressure testing it. Wouldn't be too hard to adapt a hose and regulator to it.
Now I just need the time! LOL!!!