Exhaust noise

[JDeBene]

I have a 1996 330 dancer with 454 bluewater inboards i just bought this year. I have noticed last time out in rougher waters at cruise speed of 24K that I would hear the port engine sound louder at times. It sounded like a speed boat going by me. The sound would last a couple of minutes then go away. Does this have something to do with the underwater exhaust? The surveyor told me to check the flapper valves sometime as a prventitive measure. Is this a big job?

Thanks,

 

[fc3]

What flapper valves? Don't think the surveyor knows the system. Probably the raw water pump is marginal in output. When the pump does not produce enough water, the muffler goes dry when all of the water blows out with the exhaust flow.

When were the raw water pumps last serviced?

Best regards,
Frank

 

[JDeBene]

Thanks for the answer.

The impellers were replaced this spring.

 

[Alegria]

Hi Jim,

Yes what flapper??? There is none. But I can say the same water flow from the exhaust decreases the exhaust sound. I know for me I am in a similar situation. My port exhaust water flow is significantly less then the starboard. I suspect a blockage somewhere in the exhaust flow most likely where the muffler come off the log type collector.

Some things to look at, how is the water flow from that side exhaust on the port. For me I know it is significatly less, a trickle comparted to my startboard exhaust. It is also louder and at no wake speeds in a wind you can hear the port exhaust a bit louder then the startboard.

My port engine temp risers quicker then my starboard, don't know if that is linked or not.

Make sure when you check the flow that the exhaust outlet is not in the water if it is it will be hard to judge the flow as it will be spraying water you may need someone to stand on the starboard side to level it out as you lean over.

I too had the pump and impeller replaced this season so I suspect a blockage somewhere. Check the strainer too on the raw water side it might be that easy. For me its not as it is clear...

Post back if you find anything more out! Take Care!!