Exhaust water restriction- Volvo Penta IO 3.0L SX Cobra

[imported_erick]

I just had my boat tuned up by a mechanic and he told me to check the riser and exhaust elbow for restricions. He said that the water hoses were all rock hard when the engine was running because the water was restricted from exiting the outdrive. He checked the hose that directly runs from near the thermostat to the riser and said this should flow easily, but on mine it builds pressure.

Does this sound right? If so what should I look for when I take that elbow off?

Thanks,
Erick

1998 (replaced with a 2005 long block) Volvo Penta 3.0, sx cobra outdrive.

 

[imported_erick]

Re: Exhaust water restriction- Volvo Penta IO 3.0L SX Cobra

bump?

I will be taking the riser elbow off in the morning, just wondering what to look for. Do these require replacement often, or can they be cleaned of rust (if there is any)?

Thanks,
Erick

 

[imported_erick]

Re: Exhaust water restriction- Volvo Penta IO 3.0L SX Cobra

Pulled it off and it is clogged with rust. My father wants to clean the rust out and re-use. Is this a good solution? It is only 2years old and I am not sure how it got so jammed up.

 

[Bondo]

Re: Exhaust water restriction- Volvo Penta IO 3.0L SX Cobra

All that Rust,........ Used to be Cast Iron,...........

If you're boating in Saltwater,......
I'd Replace the exhaust Manifold,+ the Riser.........

Just Cleaning it is Asking for Saltwater Intrusion into your motor.........

 

[180shabah]

Re: Exhaust water restriction- Volvo Penta IO 3.0L SX Cobra

Pulled it off and it is clogged with rust..... It is only 2years old and I am not sure how it got so jammed up.

Your engine was replaced in '05, your exhaust may or may not have been. It is very common to just clean up and repaint the manifold and elbow then reinstall them. The average life span in salt water is 5 years (some last longer, some don't) If yours are that clogged, it probably did not happen in just two years, which means that they are older and due for replacement.

Like Bondo said, when your manifold/elbow fail, they can (and often do) take the engine with them. It's a few hundered dollars now or a few thousand later.

Your Call.

 

[imported_erick]

Re: Exhaust water restriction- Volvo Penta IO 3.0L SX Cobra

the manifold was replaced when the engine was, I think the riser was also. I did find another thing today. It was a piece of rubber (probably an old impeller) in the elbow coming out of the thermostat housing leading to the riser. I pulled it out and the pressure was gone from the hoses. The temperature also dropped in the riser. I took the boat out for about 30 minutes and it ran great. When I flushed the motor, the hose was again hard. I will take the elbow off again in the morning and see if it is clogged again.