Hi,
New boat owner here (2007 FW H180, 4.3L) and trying to figure out a drive reservoir leak. I am finding a slight oily residue in bilge and up into ski locker, with the drive reservoir level lowering a bit with each outing. I have found that the bottom of the bottle where the low level sensor is located gets wet with drive oil, which leads me to believe there is a slow leak there while underway.
Based on some other threads I've read on the topic, it seems that as the outdrive heats up, it wants to push the expanding lube back into the reservoir bottle, and then it lowers again when cooled. After examining the bottle cap, it appears by design that the rubber piece underneath is made to allow air into the bottle (when cooling and level decreases) but does not appear to be vented in the opposite direction. My theory is that without that two way venting, when the fluid is expanding there is some pressure built up which forces the lube out of either the sensor nut union or the hose connection (whichever is the weakest connection).
I was thinking about cutting a "V" out of the rubber piece, and rotating it so that it just covers about 1/2 of the diameter of the cap vent hole, which will allow it to breathe in both directions, but am concerned whether Mercury is counting on the system only venting one way (as currently set-up) and don't want to ruin anything.
Anyone have thoughts on that approach? If I do take the V out of the rubber piece, and get splashing/overspill out of the cap, I can always spin it CW or CCW so it fully covers the hole again.
I haven't really done anything more to address this yet like pressure testing the bottle, screw clamping the hose etc.
New boat owner here (2007 FW H180, 4.3L) and trying to figure out a drive reservoir leak. I am finding a slight oily residue in bilge and up into ski locker, with the drive reservoir level lowering a bit with each outing. I have found that the bottom of the bottle where the low level sensor is located gets wet with drive oil, which leads me to believe there is a slow leak there while underway.
Based on some other threads I've read on the topic, it seems that as the outdrive heats up, it wants to push the expanding lube back into the reservoir bottle, and then it lowers again when cooled. After examining the bottle cap, it appears by design that the rubber piece underneath is made to allow air into the bottle (when cooling and level decreases) but does not appear to be vented in the opposite direction. My theory is that without that two way venting, when the fluid is expanding there is some pressure built up which forces the lube out of either the sensor nut union or the hose connection (whichever is the weakest connection).
I was thinking about cutting a "V" out of the rubber piece, and rotating it so that it just covers about 1/2 of the diameter of the cap vent hole, which will allow it to breathe in both directions, but am concerned whether Mercury is counting on the system only venting one way (as currently set-up) and don't want to ruin anything.
Anyone have thoughts on that approach? If I do take the V out of the rubber piece, and get splashing/overspill out of the cap, I can always spin it CW or CCW so it fully covers the hole again.
I haven't really done anything more to address this yet like pressure testing the bottle, screw clamping the hose etc.
Imagine that, you're supposed to have a leak by design:facepalm: