TROUBLE MAKER

Standard Bravo 1 drive, 1:36 gears, low water pickup...

After sitting all winter in storage, I noticed a small amount of oil on the floor below and drive and after tracing it back to its origin...looks like it is coming out of the low water pickup openings... Go figure.. Over the summer I did notice that drive reservoir, filling up just a tiny bit, but nothing I was going to get worried about.

Most likely cause of this is??? Cracked upper case? Lower case? An oil ring somewhere?

I'm gonna pull the lower off this weekend, and follow the leak up the water passage way..

Thanks

hillbilly24

f it is coming out of the water pickup it is probably just the quad seal, it is a small square cut seal that seals the oil passage where the drive splits. No big deal at all to change. you will see it when you split the drive, just make sure you fill the drive slowly or you can nuild up enough pressure to blow it again.

TROUBLE MAKER

I dropped the lower unit off the drive yesterday...and from the looks of the drive oil there is definitely water getting inside the drive. So, after dropping the lower there wasn't any oil running down the water passage way from the upper drive which is good... But, there also wasn't any running down from where the case splits either, but there was definitely a small puddle of oil sitting at the bottom of the water passageway and then slowly running out of the intake holes and onto the cement.

So, all I can think of is that is has some sort of internal crack in the very lower portion of the case letting the oil slowing seep out and of course when I'm up and running the water pressure coming into the drive is forcing water inside the drive itself.

Has anyone seen anything like this before? I'm not running a bunch of horsepower and the drive only has around 150hrs...

Griff

If its leaking out the water passage, 99.9% of the time its the O ring seals between the upper and lower. Put a new set of seals in and pressure test it 15lbs. Then if you can, do a vacuum test.

TROUBLE MAKER

As a mechanic I would tend to want to agree with that...

But, for the drive oil to reach it's way into the water passage way, it has to go through 2 o-ring seals (the one around the vertical shaft and then the one around the water passage) And if it was an o-ring I think there would also be signs of oil leakage coming from between the upper and lower cases. There also wasn't any evidence of any oil running down the passage way from where the drive splits.

I may just put some oil in the lower unit and tilt it forward for a couple days and see if anything leaks out or not..

MOBILEMERCMAN

Its about the size of a fill washer and it is located inside the water passage o-ring. Unless yours is real old.

TROUBLE MAKER

Okay I see what you're saying... I thought that small (orange colored) washer/o-ring was for the speed-o, but I guess the speed-o passageway is the one in the very front...the one that is really thick and about 3/8 inch wide. I'm still puzzled though, because when I took it apart I was expecting to see some sort of traces/evidence of the oil running from somewhere, but everything around that whole water passage way was dry...no evidence of any oil being on the walls at all..

SSComp

I had this problem. There is an aluminum "puck" that is the ONLY thing keeping the water separated from the oil. It is the flat wall you see from inside the water pickup and if you pull the prop shaft and gears...it is the wall you see in the pront of the bullet (housing). It is not solid.

Case in point is usually it passes a pressure test...yet still leaks when the pressure is off. Pressure check simply pushes the puck back into place. When your running your puting between about 80-120 lbs per square inch on the water side which forces the puck back and leaks.

Merc's only solution is to buy a new housing. They will not sell just the puck even it is clearly shown in their diagram.

After much debate between my machinist friends we decided just to JB weld it back into place. We pondered remaching, cryo the puck etc as we had the resources.

Has worked well for years now.

TROUBLE MAKER

I was looking at that exact piece wondering whether or not that was part of the casting or an individaul component. But, Mercruiser doesn't make any reference to it anywhere that I can find, so I figured it had to be part of the casting.

So, you just popped it out, put a little JB Weld around the out side and popped it back into place. I guess it's just pressed into place to begin with, Mercruiser doesn't put any glue/sealant on it?

Thanks for the info..

SSComp

Yep that's it.

Don't pop it out untill you have make sure the seal between the lower and upper in the water path housing is good.

They gave some big speech how it is "propitary" how they put it in there. Any make no other reference to it but to show it on the diagram.

BTW give thanks to "rogue" on this board who is lurking and asked me to chine in.