Mercriuser/Bravo II: outdrive oil overflows

[ArtmanAK]

I have a 1994 24' SeaSport with a 5.7L Merc and Bravo II outdrive. The oil reservoir (in the engine compartment) for the lower unit overflows after longer runs. I basically have to keep the reservoir at almost empty when cold, cause if I fill it to the recommended level and then run for a while, it overflows into my bilge. I've also had to disconnect the alarm buzzer for the oil level 'cause it drives me nuts.<br /><br />The oil is fine...no water, shavings...anything.<br /><br />Has anyone else had this problem?

 

[Capt Ken]

Re: Mercriuser/Bravo II: outdrive oil overflows

Probably have a bad cap on the reservoir. The cap has a built in check valve that allows air in, but nothing out. As the outdrive heats up, the oil expands and will overfill the tank if the valve doesn't hold the pressure. Same thing will happen if you don't screw the cap down tight.

 

[ArtmanAK]

Re: Mercriuser/Bravo II: outdrive oil overflows

Thanks Cap'n...that's exactly where it's coming out from...the small breather hole on the cap. Maybe I'll just try to give the lid a good cleaning in some soapy water and see if that stops the backflow...otherwise it should be a cheap part to replace.