Yikes...water in the lower unit.

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potter water

New member
The sight of half a cup of water coming out of the lower unit of my port Suzi was terrifying. The starboard engine was putting out only good clean hypoid oil. (Doing my winterizing).

I don't know where to go from here. Does anyone have experience with the concerns I should have about having run the engine during the summer, possibly with some water in the lower unit? I don't know when during the season that the leak started.

I've worked on a couple of old two stroke lower units and just removed, cleaned the interfaces, put in new gaskets and o rings and things were fine.

Anyone have thoughts about where most of these kinds of leaks come from? Or do they simply occur at any place where there is a seal or gasket.

I'm making a fitting to allow me to pressurize the lower unit and see if I can get bubbles. Any one else done such a pressure test and what did you use to get the pressure into the lower unit?
 
The shop manual recommends a Leakage check using a pressure gauge and a hand pump. Low pressure check 2.8- 5.7 psi. Rotate the shaft during the process. High pressure 14.2 psi not to exceed 15.6 psi. Pressure should remain constant for at least 5 minutes.
 
I'm waiting for my Suzi shop manual to show up. I've done lots of outboard work but only on pre 1990 engines, so working on the 2007 will be new. My nearest dealer is 700 miles away, so I'm orphaned here in Utah, though I do have an excellent marine shop only 6 miles away if I get in trouble. They are not Suzi dealers, but are broadly experienced.

I have a low pressure compressor that should let me keep the pressure well within the range you've mentioned. Thanks for that info. I'll keep working on my adapter for the gear case lube port and do the bubble test while I await the arrival of my shop manual.
 
potter water":k4dmz1nm said:
I'm waiting for my Suzi shop manual to show up. I've done lots of outboard work but only on pre 1990 engines, so working on the 2007 will be new. My nearest dealer is 700 miles away, so I'm orphaned here in Utah, though I do have an excellent marine shop only 6 miles away if I get in trouble. They are not Suzi dealers, but are broadly experienced.

I have a low pressure compressor that should let me keep the pressure well within the range you've mentioned. Thanks for that info. I'll keep working on my adapter for the gear case lube port and do the bubble test while I await the arrival of my shop manual.
Click to expand...

I think the idea is to use a hand pump to get to the pressures and then valve off the pump to see if it leaks down without trying to maintain pressure. The manual warns about to much pressure could damage the seals.
 
Agree with the hand pump, and watch the pressure. One of the most common causes of the seal failure is the rear seals and monofiliment. Sometimes you can just run thru some in the water --not even attached to a fishing rod! I would look at the rear shaft seals first. You probably will want to pull the prop for that.
 
Monofilament tore the seal out of a merc sterndrive I had once , the dealer replaced the seals and did the pressure test as jkidd outlined.

This is probably not your issue but I have a 1980 merc 50hp that I had problems with a few years ago (water in oil) . The dealer discovered that the shaft was pitted around where it contacted the seal in the water pump. This was allowing water to mix in with the oil. Since a new shaft was not available from Merc. I had to fix it old school. The dealer gave me the shaft and seal and a guy at our shop brazed up the pitted area then had a machine shop turn it down until the seal fit the new surface. Working great ever since. :D

Another thing I do when changing the gear oil is put a small dab of blue silicon around the threads before reinstalling both plugs.

Regards, Rob
 
Hello all,
I'm new to C-brats having just purchased '04 CD 22 in August. I have had the boat out a couple of times with no apparent problems. I just recently winterized my '03 Honda in doing so, I found milky gear case oil. I noted that the water pump stream was strong. The drain/fill and vent screw gaskets were not replaced after last the oil change (possible location for water intrusion). Another possible location is what appears to be a damaged vent tube located on the cavitation plate on the forward portion of the motor leg. The tube has a hole in it and the end is not connected to anything. There appears to be evidence of a clamp mark in the rubber tubing, but I cannot seem to see where it may have connected. Where is this connected? If it is a vaccum tube, could it suck water into my gear case?
 
The tube could be for a speedometer. There is a hole on the front of the foot and a hose that would connect to that and them go to a speedometer. Mine just deadends.
 
I had the same problem with one of my Suzuki DF50's. I think it was due to leaky drain plug gaskets. Maybe the first one third of what drained out was clear water. The total volume was about right; it was just as if some oil was replaced by water. I did the air pressure bleed down tests per the shop manual, but the pressure held rock steady. Since I knew that there had to be a leak somewhere, it occurred to me that one thing that was different when I ran the test were the plug seals. Then I vaguely remembered that the last time that I had changed the gear oil, something seemed odd when I tightened the drain plugs -- as I was tightening the plugs, the torque did not feel like it was increasing the way it should have. I was tired, it was cold and getting dark, and while I didn't like it, I told myself that the plastic gaskets might be designed to crush and that was why it felt unusual when being tightened. I was using a torque wrench and tightening to the value specified in the shop manual, trying to do everything right. I should have listened to my instincts, but these Suzuki’s are my first outboards, and I was going by the book because I had no experience with Marine engines and underwater lower unit seals.

So I had a reason to take a closer look at what was going on with the drain plug gaskets. What I saw was that, because there is very slippery oil on the gasket and plug, when it gets tightened the gasket just gets squeezed out. You might be able to see it in the picture. I was surprised to see that there was nothing to capture the gasket and prevent the extrusion. I decided that the torque value in the shop manual is not meant to be used for an oil change, especially for a plug, gasket, and case that inevitably are slippery with oil. So now when I change the lower unit oil, I tighten the plug until it contacts the gasket, and then go another turn or so, without measuring the torque. I am really not that happy about this design, because it seems that since a low tightening torque has to be used and along with an oil film, there is hardly any friction to hold the plugs securely. If I find out that something better than plastic gaskets are used on other brands of outboards, I might consider using a different gasket. I should also find out if there is a more exact procedure to tighten these plugs that I don’t know about.

The good news is that the water did not crack the case when it froze over the winter, and that operating for a season with a water oil mixture has not seemed to hurt the lower unit ‘so far’ (there have been two good seasons of running since the water intrusion).

Note, if anyone is doing the pressure test with the lower unit removed, be sure to bolt the top (driveshaft bearing housing) to the case, or the cover might blast off.

Joe
EXACT LEE

Lower_Unit_Seal_Extrusion_009.sized.jpg
 
I think the tube you see is for use as an instrument (speedometer I think) when not using the paddle wheel. I have one on each of my bf 40's. they have never been connected to anything.
 
C-cakes, do the instrument hoses blind off? In other words, are they dead ended and sealed? Does anyone know if these instrument speedo tubes enter the lower unit and the gear case oil?

Thanks,
Grazer
 
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