Before setting out on a cruise I topped off the drive oil in one of my engines to the fill line. Upon returning from the cruise, I noticed the drive oil resevoir had inched up over the fill line an subsequently noticed some drive oil in the bilge. Anyone have any ideas on what happened? Could it be a leak in the lines going to the drive? or could there have been pressure build up and somehow backwashed out any excess of oil in the drive system. I am baffled and certainly I am not a good wrench to know what happened and what I should do to rememdy the situation. Hopefully this weekend I will get an opportunity to go out and see if it was a one time occurance or a repeating issue. The engines are 01 496 mags coupled with bravo one HP drives. Thank you for all and any responses. Happy Holidays.

James

A couple of things could of happened. I'm guessing that there was some air in the line and when you were out it purged it's self and overflowed the bottle. Clean up, top off and see if it happens again. If there was alot of air, it could happen a couple of times.

Thanks cord! I'll give it a shot this weekend and see how it plays out. Thanks again and enjoy your weekend.

Are you running drive showers? If not the fluid could be the result of the drive oil getting hot and boiling lack and out of the top of the bottle...Just a thought

srpbaer, no i am not running drive showers. I was under the impression that 375 hp into a bravo hp wouldn't heat up the drive too much. I don't have any chalking on the drives and since it happened to only one side of the twins i would think it was something specific to the afftected side. thanks for the response. it is good to think about all potential causes. I think there could have been pressure buildup from running them hard/ would that be caused by the heat? And then the question again arises why didn't the other side end up with drive oil in the bilge? thanks again.

Cord, when thinking about what you posted i asked myself if it over flowed from the resevoir i would see it on the engine hatch. I did not notice any drive oil on the engine hatch. or when it overflows does it spew out slowly where it wouldn't hit the hatch(mine engine hatch sits very close to the top of the motors)? just kicking around ideas. it goes in for service mid next month so whatever it is or isn't will be taken care of.

James,

It's somewhat natural for the resorvoir level to rise and fall based on drive temps. However, you may not be losing fluid from your resorvoir. If there is no indication of leaking from the resorovir, such as streaks etc. then look closely in the bellows where your drive shaft goes thru your transom. If there is drive oil in the bellows, then chances are you have a seal going bad in the drive. This is not a major issue, but you do have to remove the drive to replace the seal. The seal of which I speak is the one where the shaft goes into the top half of your outdrive on the stern side of the U-joint. Some Bravo drives, especially X series had a nasty habit of this seal going off center, getting bit by the shaft and misaligned. This would then allow drive lube to leak thru and into the bellows and ultimately into your bilge.

Merc now makes a better seal that fairly eliminates the problem.
I don't have the part #, but your local Merc Hi-Perf shop will have it for you. I think you're in Tampa, so you might call Gene Weeks at Thunder Marine in the St. Pete area. Nice guy, very knowledgeable.

Good luck,

Steve

Hi steve, how have you been?

Thanks for taking the time to help me out. The thing I find most peculiar is that the drive oil i saw in the bilge was under the front of the engine in a few spots not near the transom. I am going to clean it up more and run it hopefully on sunday. I'll report back here if it happens again.

Thanks again Steve, Happy Holidays!

James

For my response, I was thinking of my power steering pump. When it would burp, it would just over flow. I'm thinking the same thing would be true for the reservior. The fluid is so thick, that I doubt if it could splash. There are also a couple of other things that you could check. The is a clip on connection where the hose attaches to the transom assembly. Double check to make sure that the connection is on. A gentle tug will confirm this. Also check to see that the hose connection to the clip is tight. At the bottom of the reservior is a fitting. This fitting is retained by a nut that is inside the reservior. Mine was leaking and it was solved by using a needle nose pliers to tighten the nut.

thanks again cord, I'll give those things a look when i take out the boat this weekend. have a good one