Water In Lower Unit

[Polarkraft05]

Well i made a very bad discovery today. I put off changing the lube in my lower unit until today, It has already been well below freezing here in northern missouri.

today it got to upper 40's so i went out, pulled the plug on the lower unit and the first thing that came out was straight water, id say an ounce or so.

what is the likelyhood that something was damaged? is there any way to know without running the engine?

i spun the prop with no problems or noises, then put it in gear and the prop acts as normal (cant spin in)

also what seals need to be changed so that water will not get into the lower unit?

it is a late 70's or early 80's mercury 85 hp

[Lund Explorer]

The biggest danger is having the lower unit/gear housing crack. Did you notice any fluid leak on the floor before you tried to drain it?

If you are real lucky, the leak comes from a missing o-ring on one of the two screws you removed. But, most likely it is the seal around the drive shaft. Regardless, it sounds like it is time for a trip to the marina.

[Polarkraft05]

so will the crack be visible on the outside? i was thinking the internals would be damaged, but now that i think about it it would make more sense for the housing itself to be cracked.

I didnt notice any fluid leaking, but it sits outside, so it is a little hard to tell.

also since my motor is so old, and kinda rare i doubt any marina's around me will have the parts. and i will be putting them in myself, cant stand paying someone so much just to do mechanic work. there are parts of outboards that take special skill to work on, but most of it is just basic mechanic skills.

[Jig Man]

Unless you are pretty good you better let someone look at it. If your housing isn't cracked then you probably need new seals at least. I'd rather pay a few bucks to someone who knows what to look for than spring for a new lower unit.

[Crappiebasser]

You need to have the LU pressure tested to find the leak. An ounce isn't a huge amount so there is a good chance you don't have any real damage. I have seen a lot of those older Mercs that just had a rotten o-ring on the fill plug letting water in.

[Way2slow]

The way I see it, for now I wouldn't worry about it being cracked. It has to be torn down and resealed to fix the leak and to check the gears and bearing to insure they haven't rusted. While the LU is off, replacing the water pump is pretty much a given. If the seals are all they find wrong, you are still looking at $500 or so (provided the gears/bearings are good). Shop around and you can probably find a good used LU for less. If you decide to have your's repaired, they can pressure check/inspect it when it's torn down

Your next option is to keep running that one and change the gear oil every few trips. You can run Valvolin synthetic 85-90 and save a little over what the merc gear lube will cost

[NBR]

Like Way2slow I wouldn't worry about it now. I'd refill with lower unit oil make sure the gaskets on the drain and fill bolts are in place and put a pan under the motor so if it leaks you will know in time to get it fixed before you want to start fishing in the spring. It takes some pretty low temperatures to freeze hard enough to crack the lower unit casting. My guess is that you have escapede major damage.

[Polarkraft05]

sounds like i will just keep running as usual, aside from changing the oil more often. its not worth spending 500 on a early 80's motor that is on a early 70's boat.

it will cost much more to replace the boat and engine, but at the same point i could never get over a grand or so for the boat.