Whats this beside the telltale?

[Bobbywolf]

2004 Johnson 70 4stroke.

The telltale on this is a little cap (right, on the pic) with a hole that you can direct the stream where you want it to go. But beside this is a little open rubber tube (left) that shoots air/exhaust from the outboard when running.



Can anyone tell me the purpose of this? The exhuast is all through the prop is it not? Just not really sure of the purpose here.

Rob

 

[GA_Boater]

Idle relief port. It lets the motor idle when not moving by relieving exhaust back pressure. Once the boat is moving the exhaust back pressure from the water is lessened and and flows out the prop.

 

[Bobbywolf]

Thanks. Just did some reading, after knowing what to call it. Makes sense to me now. Cheers!