Bad. Very bad.

TickledPink

I opened the gear drive fluid resevoir today and gear drive fluid burst out of the bottle and smelt of sulphur on my 2003 mercruiser 5.0 mpi with bravo 3. The bottom hose attached to the elbow where the exhaust flappers are, is full of gear drive fluid too. The flappers are still in place. There are no metal shavings. the engine hasn't been used for the past 2 years.
Google AI tells me that the sulfur smell is perfectly normal for heavy-duty marine gear lubricants. However, the combination of gear fluid bursting out of the reservoir and filling the bottom exhaust hose indicates a serious, specific failure: my outdrive exhaust gas is pressurizing the gear lube system.

Because the engine sat unused for 2 years, the rubber seals have dried out, shrunk, or cracked.
It also says to check the upper input shaft seal, top cover plate O-ring/gasket, and the shift shaft seal.
Have any of you experienced this before and can you please give me any advice that you think may be helpful.
Thanks as always.

aero3113

I never heard of this happening. It’s possible that the vent on the cap of the reservoir is faulty and causing a pressure buildup up. Then somehow the gear lube was pushing out of the drive and into the area of the shutters.

YYZRC

I think you should start with the basics. I would remove the drive and have it pressure tested.

rasbury

YYZRC said:

I think you should start with the basics. I would remove the drive and have it pressure tested.

Do you have to pull it for that?