Exhausting Question

[H2O DVL]

Or more specifically, an exhaust question.

I'm not new to boating or mechanical surroundings, but this is the first outdrive I've owned and I have a question about where the exhaust should exit the drive.

Boat's a 2005 Glastron with the 3.0L Volvo and SX drive. At idle, with the trim at about the 1/2 way point the exhaust clearly exist through the prop. However, as I drop the trim below 1/2 (roughly) the exhaust begins to start exiting from around the housing and the transom area, and very little through the prop. This may be perfectly normal operation for all I know, but vast searching on here didn't confirm anything for me.

The bellow is good (from what I can see of it) and there is no obvious signs of deterioration or deformation.

Thoughts?

Kevin

 

[Maclin]

Normal, probably. Sounds like you are seeing exhaust thru the idle relief ports at the bottom of the transom plate on the stern.

 

[H2O DVL]

A quick search on "idle relief ports" generated exactly the answer I was looking for. Ironically, you answered that posters' question too;

http://forums.iboats.com/forum/gene...s-and-still-over-reving?p=8362786#post8362786

Thanks Maclin!

 

[4now04]

That is completely normal. The exhaust will come out through the easiest path. If the out drive is trimmed up so the prop is about as high as the the bottom of the transom shield the exhaust will come out through the prop. The outlet on the bottom of the transom shield is not large enough to allow full power exhaust flow only through this port. At least some/most of the flow must go out of the prop. At idle it is not an issue.