Why DON'T the exhaust come out through the prop on my I/O 99 larson 3.0l volvo penta outdrive.?

Question

The exhause tub in the boat and in the outdrive are fine. they have no holes or rips. the exhaust just come strait out the bottom of the outdrive.

Answer 1

THINKING LOGIC

IF ITS COMEING OUT OF THE BOTTOM OF OUT DRIVE? WHERE IS INPUT TO TAKE EXHAUST TO THE PROP?

DO YOU HAVE A PIPE MISSING?

IF YOU PLACE WATER HOSE IN EXHAUST HOLE IN CENTRE OF PROP AND TURN WATER ON WHERE DOES THE WATER COME OUT

IF THIS IS DIFFERENT TO WHERE EXHAUST COMES OUT YOU MUST HAVE A PIPE MISSING

IF ITS THE SAME AS THE EXHAUST THEN ARE YOU MISSING A COVER SEAL/PLATE

Answer 2

The exhaust from the outdrive, at least the bulk of it does exit from the back of the anti-cavitation plate. you might notice rubber flappers that are bolted on there. They usually dry rot and fall off. The rest of the exhaust exits at the bottom sides of the transom plate through rubber hose about 1 inch in diameter

Answer 3

Volvo Penta outdrives have an exhaust port above the prop at the bottom of the cavitation plate - not through the prop.

Answer 4

I also concur, Volvo sterndrive systems vent the exhaust through an outlet where usually the torque fin resides on most lower units.  This is similiar to the old Evinrude and Johnson outboard motors where they also vent it out where the torque fin is.

However, Mercrusier and OMC sterndrives vent the exhaust from the prop or side outlet flaps.

Just to let you know, you must closely pay attention to the warning posted on the boat regarding using reverse with the Volvo sterndrive.  This warning I believe is about not putting the boat in reverse if you are moving forward at a rate too fast to engage reverse.

Failure to follow this warning could flood your exhaust system with water and cost big repair bills.