How to dampen noise from control cables

[daveNZ]

My 40 HP Lombardini transmits a loud buzz up the gearshift and throttle cables to the two lever head unit. At slow cruise rpm the engine is quiet (at the helm) but this buzz is very distinctive, so I am keen to do something about it. I have tested by unbolting both cable mounts at the engine; the gearshift one seems contribute the most noise.

Is it realistic to mount the fixed clamp for the gearshift or throttle cables to the boat, not the engine. This clamp to a plate that is in turn bolted to the engine, is probably where most engine internal chatter is getting in to the cables, but if the cable sheath is clamped to the boat, as the engine vibrates in its mounts, would the controls be moving too much?

The other option is to try and soft mount where the cables are clamped to the engine.

Any ideas?



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[a64pilot]

It's a harmonic obviously, try changing the resonant frequency with a weight, either on the ends of the levers or the cables themselves, just initially a temporary weight, if it works then mount better, maybe just hanging a pair of vise grips may work.


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[daveNZ]

I'll definitely have a play with that idea, maybe putting some manual pressure on the right part of the cable might alter it as well.

One suggestions is that the twin lever control housing is a cheap variety, and should be changed. That would cost ? And I would rather prevent the 'noise' getting in to the cable in the first place. The cables are good quality, Morse/Teleflex from memory.


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[daveNZ]

I have tried unfastening both cables from the engine, and the 'buzz' has disappeared. The gear shift one contributes the most noise. Any thoughts on soft mounting the engine end of these cables?