What is this in my drive oil reservoir

[MarcelSydney]

Maxum 1800 SR with 1999 mercruiser 4.3L V6 with Alpha One, gen 2 (i think)
Engine #OL 323311
Drive#OL140489

I was doing in the engine bay today and went to top up drive fluid but noticed this milky sludge at the bottom of the reservoir. I hadn't noticed previously. It was changed about 6 months ago. I do check levels regularly, but only noticed this time as I had my head right near it tightening something else. So not sure how long it has been like this.
Is this water?
If so, where should i be looking to work out where it came from.
About 6 weeks ago there was heaps of rain while on a floating pontoon without a cover, and the bilge pump didn't turn on. The water was in the bilge up to about the starter motor (i.e a lot). Could it have found its way into the drive from the back somehow?
Or is it not water and is something else?
Thanks guys

 

[Bondo]

Ayuh,..... Those bottles tend to collect sludge, so should be removed, 'n cleaned every year or two,....

You could pull a sample of the oil from the bottom drain plug on the drive, 'n look for water,.....
If clean there, odds are the sludge in the bottle is from condensation,....

 

[MarcelSydney]

Thanks. Ill try that.

 

[nola mike]

About 6 weeks ago there was heaps of rain while on a floating pontoon without a cover, and the bilge pump didn't turn on. The water was in the bilge up to about the starter motor (i.e a lot). Could it have found its way into the drive from the back somehow?

Probably not into the drive unless you had a bad input shaft seal, but definitely into the bellows. You need to pull the drive ASAP and check out the u-joints, gimble bearing, etc

 

[MarcelSydney]

I thought i may need to do that (pull the drive) from other stuff I was reading.
I haven't done it before. When you pull the drive off, I cant work out if there is a basic list of things that are replaceable/consumables? Gaskets or seals or the like?Is there somewhere you can point me?
I believe i would need bellow adhesive at the very least.
Cheers