check valve

[high tide3]

what is the purpose of the check valve at the bottom of the transom housing on a 290 outdrive

 

[Don S]

Re: check valve

If it's OEM, I have no idea what you are refering to? Can you take a picture of it ????

 

[Robj]

Re: check valve

I have a 290 and there is no check valve on the outdrive. Maybe you are mistaking it for something else? Pix will help.

Have a great day,

Rob.

 

[Maclin]

Re: check valve

It is an exhaust check "valve". There is a two-hole port at the bottom of the exhaust y-pipe that exits thru just above the bottom of the transom mount. It is covered from the outside by a rubber flap and kept against the opening by the mounting bracket.

I am unsure of the actual operation of this, but it does allow exhaust to exit at a point above the main exhaust outlet at the end of the cav plate (not shown).


Here is a pic off mine. For reference the exhaust bellows is at the top, then the check valve port housing with the rubber flapper (small black rectangle) right above the anode at the bottom of the mount and then the bilge drain on the transom. The rubber flapper is attached at the bottom behind the zinc anode with a mounting tab that presses the flapper up against the holes of the check valve port.

 

[Maclin]

Re: check valve

For whatever this is worth, the rubber flap on mine had relaxed from its' original shape and was not against the holes, in fact there was quite a gap. I took it off and turned the rubber flap around. This allowed it to conform to the correct shape and seal the valve ports from the outside.

 

[Don S]

Re: check valve

Forgot about that one, and I owned one less than a year ago.
It's an exhaust flapper valve that closes when the engine isn't running to help prevent water from being pushed up the exhaust from stern waves and wakes. The next newer model went to open ports.