1986 150 yamaha water in my lower unit

[sven]

Thanks. I'm probably gonna get the LU pressure tested to see where its leaking. If it is I may just re-seal it. I noticed the washers on the fill and vent screws look pretty shot so maybe thats the problem. When I drop the LU i will inspect the shirt rod. I'm hoping the previous owner may have replaced the shaft. If it looks shot then I may just run it till it fails on me (i fish only in Sandy hook bay in nice weather and have towboat ins) or dump it and get myself a new motor this spring before i put it in. Cash is the main factor in making that decision.... seems to always be unfortunatly.

[willy]

On a previous motor of mine the lower unit had been serviced just before I bought the boat. Being foolish I trusted the mechanics work and just checked and found the oil clean and ran the boat half the season before I checked the oil and found it was all milky looking.
I changed the oil, and replaced the washers which should be done each time and were not, ran the motor the rest of the year and each year after and no more milk.
It was the washers, also if you have a mild leaking seal somewhere there are some fluids to put in your oil which will seal the leak and they do work. I can't remember the name of it now but according to a marine mechanic it does work well unless the a=seals are just boken or rotted bad, good luck

[Monkey Butler]

Taking off the lower unit doesn't give you a better view of the shift shaft. You can only get a peek at a tiny section of it rigt below the where the lower mount bolts are on the midsection.

Ebay would be a crap shoot and you could get stuck with another one that leaks. I'd change the oil and run it for a trip or two and then see how much water you get. Maybe you can live with it with more frequent oil changes?

If you were willing to DIY I would try just doing the seal under the water pumo first and se if that helps.

For $800 you wouldn't be getting an OEM Yamaha but more likely a new clone by Sterndrive Eng.

http://www.sterndrive.cc/Merchant2/m...ory_Code=SE416

They have made replacement Merc Alphas for a while and now have outboard lower units.

[sven]

Is there any way to inspect the shift shaft without pulling apart the whole motor?

[Monkey Butler]

Originally Posted by sven

Is there any way to inspect the shift shaft without pulling apart the whole motor?

Look at the forward edge of the midsection just below where the lower pivot connects.



You can just catch a glimpse of the shaft. It is as thin as a pencil to start and you won't really be able to tell what sort of shape it is in from wat you can see but hopefully what you will see is tat it has been replaced at some point and is now nice shiny stainless steel. You could test the strength of the shaft by removing te lower unit and then holding the top of the shaft (right under te block) while at the same time having someone insert a suitable tool into the bottom of the shaft in order to apply torque to see if it is solid. Be aware that this may ultimately turn into a destructive test if the shaft is on its last legs. Here is a link to my old thread about my shaft replacement that shows some photos of the process and a picture of the shaft itself on the last page:

LINK

[phatdaddy]

can you get to it with a magnet, that'll tell you if its stainless or not..

[Monkey Butler]

Here is what the shaft looks like:




It rots mostly at the very bottom which is not visible with the motor together:



Im not sure but the coupler at the bottom may be SS even on the steel shafts.

[sven]

I took the LU off today and got a glimpse of the shaft and it was unfortunatly corroded. It feels like it still has some meat on it (at least thats what I'm hoping). I'd say if the shaft is around 7 millimeters diameter, the thin section due to corrosion (that I can see) is maybe 5 mm. So I'm going to pressure test it, re-seal (maybe I get lucky and its simply the crappy looking washers on the vent and drain plugs....make it nice and easy), throw it back together and run it. No funds at the moment to look for a new (used) motor. I'm just hoping it will last one more season and I can swap it out in the fall.

Anything I can do to stretch the life of the corroeded shaft for a couple of months? I guess I could throw some grease to help slow the exisiting corrosion for a while. Take it easy on shifting is another I guess. Anything else? Anybody have any ideas?

Thanks for everyones advice!