Water in lower unit

[astrobud311]

Ok well I just got back to the states after my quick deployment to the middle east. I decided to do some much needed maintenance and start with chanigin the lower unit oil on my twin 2004 200hp HPDI's. No issues with the stbd motor besides some hair on the mag plug but it was just a little bit. Port motor on the other hand not so good, I pull the plug and it seems as though the plug is defferent (bigger) than the stbd motor, and I get milk out of the lower unit. This is my first time doing the lower unit oil on these motors as I've only had it for a short period of time. I bought all new upper and lower plugs and gaskets but that port drain plug is much different. My question is what could be the culprit letting water in the lower unit and is this something I can fix myself? I was thinking maybe the prop seal or the oil seals under the water pump or shift shaft. What do you guys think??

[99yam40]

pressure test to see what is leaking, service manual should give specs and procedure. Sounds like someone has modified you plug, it could be the problem

[rodbolt17]

ALL the plugs have the same thread size,at least from the factory.
the magnet plug MUST go on the bottom NEVER NEVER EVER in the top.
could be someone mommiciced it in the past,it happens.
now its time for a pressure test and possibly a reseal.
the left hand case is way beyond even the above average do it your selfer.

[astrobud311]

Rodbolt, where are you located? I have another issue with the stbd motor rpm's at wot. I'm located in Va Beach and would like to take it to someone that knows what there doing. You say a reseal is beyond the regular do it yourselfer? I was looking at pulling the whole lower unit and repacking the oil seals under the water pump drive shaft and shift shaft.

[rodbolt17]

located in colington NC. on the outer banks.
did not say a reseal was beyond the average backyardigan.
said a reseal on a lefthand case was.
reseal on a right hand case is typically 3 hours,left hand with a one piece propshaft is about 5 hours.

[astrobud311]

Gotcha rodbolt. do you work for a marina? Trying to get a name here as I don't really have a good yamaha tech in my area and you seem to really know these motors. Besides I usually fish out of OI anyway.

[rodbolt17]

pm me.
yes I work two jobs.

[ausnoelm]

I guess (stating the obvious)the first thing for you is to get the old water/oil out of the gearcase and give it a bit of a flush and get some new oil in it, salt water left on gears is usually not a good thing, especially seeing as it may have sat for a while already and it could be a while before it is fixed

[astrobud311]

Ok well I finally got to the boat today and did my leak down test on the port lower unit. Service manual says 10 psi for 10 seconds, well I could barely get 5 psi pumping so fast my hands hurt. Dropped the lower unit, pulled the water pump off, used some soapy water and found my leak. (see bubbles below). I also noticed oil leaking out of the little hole in the lower unit below the vent plug??? Now I just need to figure out which seals to replace and how to get it done. Here's the pics.

[rodbolt17]

2 seals and an oring.
takes 10 minutes now.

[astrobud311]

Yeah but how do you get the cover off?? I took the 4 bolts out and that cover is stuck on pretty good. I know the two oil seals are under the driveshaft housing cover. I was thinking about just having the whole thing repacked while it's off anyway. In the meantime I was gonna go ahead and do compression checks, change the strainer filter, VST filter, filter in the cup, and spark plugs on both motors. Let me know if there's any tricks to getting that cover off,, or just go ahead and get all new seals for the lower unit.

[rodbolt17]

2 screwdivers, carefully pop the drive shaft bearing housing out.
DO NOT crack the area where the plate sits.
or call an FC.
rodbolt17 FC2 ret.

[99yam40]

It never hurts to reseal the whole thing, especially since you have had it sitting for an unknown amount of time with water in the lube. Maybe a good idea to inspect the bearings and gears. Just a thought

[astrobud311]

Yeah I am def thinking about getting the whole lower unit repacked. I'm sure it's never been done and figured I might as well just do it now while the lower unit is off the motor and I have to wait for the new water pump parts to come in anyway. Anyone have a ball park figure on how much it cost to get the unit repacked.

[astrobud311]

hey rodbolt check your PM's. I can't get that cover off and I don't even see it in the parts breakdown.