Engine Sound

[RicM]

I have a 2003 TE with the Yanmar 6LP motor. I have noticed that above 2800 RPM when fully warmed (running home) I hear strange sound that almost seems like the engine is "skipping", an irregular "bh , bh, bhbh bh" sound. Now I know that a diesel can't really "skip" and it feels like the engine is pushing smoothly. The exhaust shows the usual bit of white "steam" like emission, and all gauges show normal. Any ideas? I'm wondering if it could be water action changing the exhaust note at speed when the boat is in a certain attitude. I tried trimming up and down with no apparent change.

[Cape Codder]

Ric,
I think it is the exhaust, and water riding up over the opening changing the tone. I have the same sound changes on mine
When my brother had his Albin in the mid-90's with a Peninsula, the exhaust was on the starboard side and had no stainless ring around the exhaust port.
Quite often I rode out back in a deck chair, and the sound was more pronunced.
Here is my attempt to decribe:
Wum, wum, wumwum, wum, wum.....

[Russell]

I notice the same sound in my exhaust and it depends on the wave height and direction. Watch the exhaust and you will see it covered with water and then blow it out in a pattern similar to the exhaust note changes. If you stand near the exhaust you will change the angle of the boat and the sound.

[RobS]

Ric, play with the tabs to change the exhaust height when running and see if the noise is effected, riding it starboard down should keep the exhaust free from water flow interference.

When you hear the noise check the tach - does the needle fluctuate at all or stay steady?

You mention "running home" - was this coming from Boston on the rough water?

[jcollins]

Mine is more like Wum, wum, wumwum, wum,WAP, wum.....

When friends pull up next to me on the starboard side they get sprayed.

[fairtide]

Walter Mitty would have written that it was pocketta-pocketa-kweep and that he swooped over the side to repair what would have resulted in destruction of a large cruise ship. For those who I've confused, see James Thurber's short story, The Secret Life of Walter Mitty. For serious anwsers to the strange sounds, I would agree with what has already been offered.

[fairtide]

Walter Mitty would have written that it was pocketta-pocketa-kweep and that he swooped over the side to repair what would have resulted in destruction of a large cruise ship. For those who I've confused, see James Thurber's short story, The Secret Life of Walter Mitty. For serious answers to the strange sounds, I would agree with what has already been offered.

[Mariner]

I noticed this type of sound once on our last boat. It got worse with time. At some point it became clear that it was a clogged fuel filter, as the occasional "miss" grew to be an overall constant loss of power. I replaced the element and it went away.