Gear Oil Lower Leg

[OverHulled]

Hi All,

New to site, and would like to ask some advice with an issue.

Engine: 90hp 4 Stroke ELPT
Year:2000

The issue started with no water from pee hole, on removal of lower leg and water pump cover i discovered the water pump base plate corroded, so decided to replaced the complete water pump setup which included water pump base plate and the seal that fits under the water pump base plate, new gaskets, wear plate, impeller and water pump cover, took it for a 20km test run this morning in fresh water and had a good solid stream from pee hole, when home noticed white substance coming from the water inlet, when the motor was in the down position drained lower gearbox and white gear oil came out.
The manual page is confusing and it highlights seals lips facing up and seal lips facing down on base plate, there is no recess for a seal on the top of the water pump base plate and none on the original removed. is there an additional one below on the drive shaft.




Any help appreciated.
Cheers.

 

[galamb]

I might wander around here a bit so hope I don't loose you.

First off, there is no other seals below, (so down near the gears) the two seals that you mention. Immediately below them is the upper bearing carrier and the needle bearings which guide the uppermost part of the drive shaft as it exits the top of the lower unit.

It sounds like you "didn't" replace that pair of seals that are kissing each other (lip to lip contact). If not, that could be your issue. If you swapped everything out "above" them, they could be suspect. You mention the "seal" under the plate, but believe you are talking about the "gasket" under that metal plate as opposed to the "oil seals" that the shaft passes through which are below the cover which is below the gasket and metal base plate)

Second, you make no mention of replacing the seal on the shift-shaft where it enters the lower unit. There is an o-ring (under the bushing that is held in place with the two screws - kinda triangular thingy where the shift shaft enters the lower unit) and there is an oil seal in the hole where the shaft itself goes through. That is another two points of potential water intrusion.

The next possible place that water could be getting in is with the little seals (washers) on the fill/vent and drain screws on the lower unit. It's a good practice to replace them every time that you take out those screws (especially if you only service the lower unit every two or three years).

Sometimes these various seals are "fine" as long as you don't touch anything, but once you pull the lower unit and replace "a couple of things" you disturb other things and cause a new issue.

You can take your lower unit into a dealer and have a pressure test done. They will submerge the unit, apply some air and look for where the bubbles are coming from which will quickly identify the point of failure - of course there is a cost associated.

Alternately, if you have some minimal equipment - tub of water large enough - air compressor or air source (plus a fitting that will seal well with the fill hole) to pump 10 or 15 pounds of air into the unit yourself, this is something you can do "in your backyard".

If neither is viable, replacing the oil seals on the drive shaft and the o-ring/oil seal on the shift shaft is not an expensive proposition, and with a 16 year old motor is certainly not something that would "hurt" to do in any event.

 

[OverHulled]

Graham
Thank you for the reply,

It sounds like you "didn't" replace that pair of seals that are kissing each other (lip to lip contact). If not, that could be your issue. If you swapped everything out "above" them, they could be suspect. You mention the "seal" under the plate, but believe you are talking about the "gasket" under that metal plate as opposed to the "oil seals" that the shaft passes through which are below the cover which is below the gasket and metal base plate)

That is my concern that you mention two seals (that kiss each other) under water pump base, the original water pump base only had one and the new kit had only one also, which i replaced along with both gaskets either side of water pump base.

The shift shaft o-ring you mentioned was never changed and have it here, which was in the kit but no oil seal, the fill/vent and drain screws washers were changed for new ones, thinking now i may have placed the one seal with lip facing down as in photo where manual says UP and supposedly a second seal lip facing down.

Photo of original water pump base with original seal. Is this where the two seal you mentioned are supposed to be, also what would be the best way to flush all the contaminated oil out of lower gear casing. diesel/kero or just refill with new.

I will pull the lower leg and do a pressure test before removing replaced items to see where air leaks are coming from, which i should have down before testing in water.


regards
OverHulled

 

[OverHulled]

Update:

Found the problem the seal i replaced was cut up, ordered two new seals, replaced, completed pressure test and held at 12psi for duration until pressure released.
Happy days.