Mercury Outboard Water Leak (Update)

[chillywillie]

So I have a 25HP Mercury that is now 13 or 14 years old.  I bought it new and it has been awesome, I can't even guess the number of hours that are on it.  I've done no work to it other than changing the oil and I've changed the plugs and fuel filter once.  Because it's been so reliable, I'm not much of an outboard mechanic.  When I put the boat away last fall I noticed there was a water leak in the motor cowling.  It's not an internal motor leak so I assume it's a water line fitting somewhere.  Anywhere in particular I should look to find the leak?  I don't recall seeing anything last fall when I was trying to see where the water was coming from.

[Mac Attack]

The small diameter plastic/rubber hose that goes to the "pee" outlet on the side of the motor.
This is where you see the small stream of "tattletale" cooling water coming out of the side of the motor.
The plastic line may have come lose or cracked.

This "pee" stream keeps you aware that your water pump is still pumping water.

Speaking of which, you didn't mention that you have serviced the water pump impeller.
Do so.
An ounce of prevention...........

Also, I would replace your propshaft seal.
Maybe even have the lower unit pressure checked while you're at it.

Good luck.

[fishlessman]

x2 on replacing the pump,  they tend to fail at iceout if you are not changing it often enough. especially if the line starts to ice up

[chillywillie]

I'll have to hook it up to the muffs and look for this line.  I looked last fall and wasn't able to see where the water was coming from but it was leaking pretty good.  As far as the pee stream it's super high pressure and always has been.  I see some motors with barely a dribble and this one shoots a solid stream of water 6 feet.  I've been telling myself for years that I should replace the impeller but it's just been so strong I keep talking myself out of it.  Sometimes when things get taken apart and repaired they are never the same.  As for the lower unit seal - I'm like a broken record this motor is great.  I change the lower unit oil every fall and there is never any trace of water in it.

[fishlessman]

with the pump its a two part problem, it hardens up a little and one blade breaks and wipes out them all. then theres the problem that the bolts seize because you waited too long and corrosion  strips the aluminum when you remove them

[Mac Attack]

with the pump its a two part problem, it hardens up a little and one blade breaks and wipes out them all. then theres the problem that the bolts seize because you waited too long and corrosion  strips the aluminum when you remove them

yup

[chillywillie]

Well I guess that ship has long since sailed because the lower unit has never been off, I guess we'll see how much trouble it causes me.  The good thing is that it's seen almost no saltwater use, has been used in primarily clear water lakes and has always been stored in a garage.  I did check the lines from the motor to the pee hole last night in the garage with the motor not running.  All lines and fittings appear in great shape so I'll have to fire it up and see what I can see.  Are there any other water lines under the hood other than the one going from the motor to the pee hole?

[MG39]

Totally unrelated to your water problem but these cold mornings can cause havoc to your motors.

The water in your tubing freezes and you have no water coming out the tube cooling your engine.

I found an old electric blanket and I throw it over the motor in the morning and it works slick.

[Mac Attack]

Well I guess that ship has long since sailed because the lower unit has never been off, I guess we'll see how much trouble it causes me.  The good thing is that it's seen almost no saltwater use, has been used in primarily clear water lakes and has always been stored in a garage.  I did check the lines from the motor to the pee hole last night in the garage with the motor not running.  All lines and fittings appear in great shape so I'll have to fire it up and see what I can see.  Are there any other water lines under the hood other than the one going from the motor to the pee hole?

Not sure if there is a thermastat in it.
If so, check the cover of that for a gasket leak.

[chillywillie]

Looks like it's off to the specialists.  I verified there is no leak at any visible lines or fittings.  It appears to be leaking from between the bottom of the motor and lower cowling and I have no idea how to get all of that apart.

[Turnbuckle]

Any chance it’s just draining by design. The new Mercs anyway use water to cool the fuel pump and trickle out around the cowling in an unexpected place looking like a leak. Fooled me at first, but it’s normal. Not sure on the older ones.

[chillywillie]

I don't think it's by design, I don't remember ever seeing water in the cowling before.  It's got some decent pressure to it as well and it leaks enough that when I have it trimmed up all the way it runs out the front of the cowling into the boat.

[gunrunner]

Most likely the base gasket.....A pain in the butt!

[Turnbuckle]

I don't think it's by design, I don't remember ever seeing water in the cowling before.  It's got some decent pressure to it as well and it leaks enough that when I have it trimmed up all the way it runs out the front of the cowling into the boat.

Sorry, I missed the “in” the cowling leak.  thought you were noticing water flowing out of an area of the external cowling beyond the pee stream, which on the newer ones is normal.

[chillywillie]

So I finally got the boat back and need to get everything re-installed because I'm jonesing bad for trolling.  The water leak ended up being a bad water jacket gasket.  Mercury was having parts ordering difficulties and it took over two weeks to get the parts in.  I had them change the impeller as was seeing as it's the original one and 14 years old.  The old one was working perfectly and now that it's been changed my luck will have this one die on me within a year...

Hopefully I'll be on the water this week.