Bo Knows

Always had jet boats but last year I bought a boat with twin mercruiser outdrives. Always one to stay on top of maintainence I changed oil in both outdrives. I went to the local merc dealer to get the proper oil & he said mercruiser hipo oil (green) was the only oil to use so I bought & installed it. At the end of the season I decided to drain out old oil & install fresh oil in case it had become contaminated. The oil drained out of the drives ok but I thought it looked a little sludgy. The reservoir however didn't drain. Upon further investigation I discovered that the oil in it had turned to some kind of green muck. I had to remove both reservoirs, scoop out the muck, flush & clean lines to outdrives, & wash out reservoirs ! I should also tell you that I installed drive showers on both outdrives at the beginning of last year & I dont race the boat or run it very hard. I thought this might have been some kind of fluke or something but when I went to help a friend winterize his boat who was also using this green oil we found the same thing in his reservoir! It was then that we both decided to install Mobil One gear oil. Is this OK to use ? Has anyone else had this problem ?

Wally

iTrader: (1)

Hmmm, i dont know what to tell ya. I changed my drive oils from the merc stuff to the Red Line shockproof Heavy synthetic when i had both drives rebuilt. Never had a problem since and that was 3 yrs ago. My drives are the TRS and i dont have drive showers on them. I'm wondering if maybe your not running the drives long enough for them to heat up to warrant a drive shower and thus causeing condensation inside the drive and getting a little contamination. either that or a seal may be going bad someplace! May be a good idea to have the drive presure tested to be safe!

BajaBoss252

When I drained my Bravo drive last year I had the same problem with my resevoir. It was clogged up and I had to remove it and clean it out. I bought the boat used so I am not sure if it was like that all season or not. I guess I'll have to wait until this season to see if it does it again, but I did not put Merc oil in it.

Ted

Thunder1

Have three Bravo's which I service every year and have not heard or seen this problem... Then again a cooler climate may contribute to this phenemon... I would think that the local Mercruiser dealer might be able to shed some light on the issue...

Karl

jafo

I'm also using RedLine Shockproof Heavy (two seasons now).
No more sludge, no more fuzz on the magnet, cooler temps.
How's it goin' Wally?
Jim

rjcardinal

Its probably due to water contamination of the oil. Either from condensation (cold climate) or a leak in the outdrive. If its a milky sludge then its water. Just before I change mine every year the oil in the reservoiur has a layer of water from condensation at the bottom about 1/8 inch thick. If your condensation is worse and you let it go longer it could plug the hose.

Ron

29 OUTLAW

There's only one reason why I still use the merc HIPO oil. I've read that the merc oil is formulated so that it can be emulsified with as much as 40% water and still provide adequate lubrication. This would come in handy in the event of a sudden severe leak that you were unaware of. Synthetics apparently cannot mix with water in the same manner.

checkmate981

I agree with outlaw 29,
I have been running merc high performance gear lube for 8 years and never had a problem..What oil did the drives have in them before?Maybe they did not mix well if they were different?I would run it once come spring and re checkTo check for water.I never had a problem with condensation here(New York).
Good luck
Dave

Blueman

I thought merc. hipo gear oil was blue.

Vinny P

I always run Merc. hi-perf. oil and never had a problem. It is possible that whoever had the boat previously, mixed oils. In most cases, I have heard that the oil will foam and not mix well. However, your problem sounds to me like water got in somehow. I wouldn't put those drives back on untill I pressure and vacuum checked them.