Need help understanding 496 Mag HO drain actuator assembly

[Old Man In The Sea Ray]

Greetings,
Having recently replaced my raw water impeller and flushed the system, I decided to add a thru hull sea water scoop, strainer, and a flushing tee. I'll abandon and plug the hose from the outdrive. Midway between the pump and transom I run into this:

Here's my confusion. The red hose (sea water in) goes thru this device and into the pump. It looks like a tee comes out of the bottom into the black hose (sea water return). Please explain the operation and function of this actuator.
TIA
Russ

 

[techmitch]

Can you post the parts list that goes with those #s?
Where does #9 go and what size/type of hose is it?

 

[Old Man In The Sea Ray]

Can you post the parts list that goes with those #s?
Where does #9 go and what size/type of hose is it?

Good question, I've searched. #9 is a small (3/16"?) air hose.
I'll let you know it's source tomorrow.
https://www.marineengine.com/parts/...-ho/0m026000-thru-0m319190/water-drain-system

 

[blaster]

Woody posted a diagram on the air actuator drain system for the 8.1.

http://clubsearay.com/index.php?thr...o-my-mercruiser-inboards.107775/#post-1288988

 

[paulswagelock]

When you pump it up with air, the actuator slides positions and the sea water drains to the bilge for freeze protection. Release the air and it goes back to normal flow path. So the small line goes to the air pump on the front port side of the motor. The bottom remains open to the bilge.

 

[Arminius]

When you pump it up with air, the actuator slides positions and the sea water drains to the bilge for freeze protection. Release the air and it goes back to normal flow path. So the small line goes to the air pump on the front port side of the motor. The bottom remains open to the bilge.

Does the air pump shown in the "winterization" section of manual have any other function?

 

[paulswagelock]

Not really. On the 496 it also pumps open the collector on the lower port front of the motor. It is a gray plastic piece with multiple water hoses on it. It also pumps open and allows sea water to drain out of the block and other passages for extended cold weather operation.