Lower unit leak

[OverRHeads]

I have a 1998 3.0L Mariner 225 EFI. It had always been kept in an attached garage until last winter when it was moved to an insulated (but not heated) 10x30 mini storage.

This past spring, after the boat had not been used for about 2 months, I noticed a very small puddle of lower unit lube on the concrete floor of the storage stall. Naturally, I assumed I had a worn or torn seal so I took it to the dealer and had new seals installed in the lower unit along with a new water pump while the lower unit was off. It had never leaked before this time even during times of not using it for equal amounts of time and had not done it since..............until now!

I stopped by storage today and noticed that I again have a small pool of fluid (approx. between a quarter and half dollar in size) below the skeg. I do not like fluids leaking from areas where they shouldn't but I question this two winters in a row.

Since this boat has never been stored out of an attached garage, could the cold have something to do with it? We just climbed out of 10 days of weather where we were below zero at night and only in single digits during the day. Pending there is no water in the lube itself, is there expansion in the lower unit lube when it gets extremely cold that would cause a small leak? I ALWAYS trim the motor all the way down and store it that way in order to drain ALL water out of it.

Any help would be appreciated!

[EuropeanAM]

There are several possibilities!

Before we get too deep into this.... you referred to this puddle as "fluid".

Have you determined "for certain" that the fluid is GEAR LUBRICANT, and not oil, gas, water, etc?

Was the gear lubricant changed just before it was placed in storage (as it should have been)? Perhaps overfilled (pouring out of the vent screw)?

Sometimes, a piece of carboard, paper, or plastic on the ground below the engine may be very helpful when trying to determine the "type" of fluid...

[OverRHeads]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EuropeanAM &raquo;</TD></TR><TR><TD CLASS="quote">There are several possibilities!

Before we get too deep into this.... you referred to this puddle as "fluid".

Have you determined "for certain" that the fluid is GEAR LUBRICANT, and not oil, gas, water, etc?

Was the gear lubricant changed just before it was placed in storage (as it should have been)? Perhaps overfilled (pouring out of the vent screw)?

Sometimes, a piece of cardboard, paper, or plastic on the ground below the engine may be very helpful when trying to determine the "type" of fluid...

</TD></TR></TABLE>

I am 90% sure it is lower unit lube. It is very thick and slimy like the high performance lube I use.

It was not changed in the Fall but it was changed last Spring when the new seals and impeller were installed. I use the boat in all seasons and have always changed the lower unit in Spring.

Should my next move be to clean up the spot and put a piece of paper under the motor to determine what is leaking? Since it has not been used in a few months, I would assume it is not water or gas as they would have dried by now since the last use.

Thanks for the assistance!

[EuropeanAM]

Since I suspect you have freezing temps there, the best move would be to drain the gear lubricant NOW. Be sure to drain it into a container that will allow you to visually inspect the contents for water.

If water is found, I would have a pressure test done "promptly".

[OverRHeads]

Do I need to heat the lower unit with a space heater to make the lube flow since it is cold?

[1000yards]

I had same problem with mine last year - assumed (wrongly) it was not lower unit oil but fuel / 2 stroke lube 'draining' out.

I had lost the shift shaft seal, letting water into lower unit - when it froze it pushed the remains of the shift shaft seal and carrier out the rest of way but luckily I found it during yearly water pump change and it seems no other damage was done - have been checking lower unit lube every trip since to keep an eye on it - no water, no metal so maybe I got lucky!

I just drained again to be sure as temps here in TX went down to 11 or so last weekend......had to put the heater near it to get the lube to flow.

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by OverRHeads &raquo;</TD></TR><TR><TD CLASS="quote">Do I need to heat the lower unit with a space heater to make the lube flow since it is cold?</TD></TR></TABLE>

It certainly would not hurt, however, you must use EXTREME CAUTION. There is always some amount of fuel and/or combustible oil in and around the exhaust- so DO NOT apply "direct heat" to the gearcase!

[Tim Powell]

+1 and follow the new filling procedure

I lost a case do to the heat build up and the height I run....causing the oil to expand and push out the seal