How doomed is my lower unit?

[TruckDrivingFool]

Got my 70 Johnson 115 running today for the first time in the year that I've owned the boat.

It seems to shift alright but when I dumped the fluid out and this is what it looked like. Is it doomed? Anything I can do now short of rebuild/replace, or just run it until it dies?

 

[Sixmark]

Re: How doomed is my lower unit?

You may not be as bad off as you think, while rust is never your friend, metal shavings and/or chunks are worse.

Water is obviously finding a way in somehow and it could be as simple as plug gaskets to fix it. You could pressure test the lower unit to see where it's coming from.

Try to find and fix the water leak first, then replace the gear lube, run it for a short period of time and then drain it again and see what comes out. If you are lucky it was just surface scaling and may just work itself free and can be drained.

 

[Sixmark]

Re: How doomed is my lower unit?

The other option is to open the gearcase and clean it out which will be a little more labor intensive but will probably yield better results and give you a better piece of mind.

 

[TruckDrivingFool]

Re: How doomed is my lower unit?

I did do a flush already as I refilled it I kept pumping fluid in until it came out the top clear so perhaps I'm halfway there. I'll run it and do it again.

How would a shadetree such as myself go about pressure testing the LU?

 

[jonesg]

Re: How doomed is my lower unit?

How would a shadetree such as myself go about pressure testing the LU?

Install new seals every time you open the drain screws.
tAKE IT OUT FOR A RUN AND CHECK THE OIL AGAIN.
If no water is getting in you don't need to do anything more.
My oil was worse, new drainscrew seals fixed it.