Throttle control box noise

[Weymouth1]

first post so apologies if this has already been asked. I have a 2006 Suzuki DF90. Whilst coming back from a fishing trip yesterday I noticed a humming noise coming from the Throttle Control Box (4000-5000rpm constant speed) - it sounded like an electric shaver running?????
I use the boat regularly and never noticed it before, i traveled about 6 miles home, no alarms, good pee stream and no warning lights, I usually have the cabin door open so this would drown out any noise previously, yesterday due to the cold i had the door shut and could hear this strange sound.

i started the engine this morning, no problem at all as per usual, but putting my ear by the throttle box could hear a feint noise again, it must get louder as i accelerate?? (i only had her on muffs on tickover today)

is this anything I should worry about or has it always been there and i haven't noticed it before do you think?
It sounds almost like a very high speed vibration or rattle - its not the audible alarm (I dont think) as this bleeps on start up as per usual.
Thank you for your help.

[Weymouth1]

Noise

Anyone any ideas please??

[Solarman]

noise in control

Not unless you have a warning buzzer mounted in, or near the controls (maybe under the dash, and echoing into the control box)?

[Weymouth1]

Noise

Thanks for the reply, no I have no warning buzzers - the only ones that I know of are in the throttle control box (which is side mounted).
Does anyone know how many are in there? The one I have that sounds on start up is very distinct and the noise I can hear when running is much quieter so I don't think it's the same one - if there is only the one does that have varying tones??
Thank you again

[Solarman]

df90, 2006, humming at controls

If your warning speaker is mounted in the control, it can be making different sounds. If making lower vibrations/ humming sounds, it could be due to connections getting poor/ corroded/ dirty somewhere in the wiring system. If any electrical devices have been added to the boat, there might be a voltage leak, or any poor ground connection that could have changed paths, due to poor connection, and now going through control cables, or wiring affecting the buzzer.
I would inspect and clean all connections at battery(s), and battery switch, making sure all connectors are good and clean. Then start checking any ground connections.
If any other electrical devices have had problems, they could be suspect.
Good luck, keep us posted.

[Weymouth1]

Noise

Thank you
I have borrowed a stethoscope so will try and narrow it down once I can get out again - gales this weekend will stop me trying it this weekend, but will post my findings (it may help others)

[Harper]

Is it possible that it's merely something vibrating inside the control box? Maybe something loosened up a bit, or something has worn, or some plastic part got caught at some point and cracked. Could be just some mechanical part that is sensitive to certain frequencies and vibrating loudest at the higher RPM ranges.

[Weymouth1]

Noise

Thanks for that
My initial thought was it might be vibration but its that fast I couldn't think that it was vibration - you think of the sound of an electric shaver.

Does anybody know whether it is much of a job to open the control box to have a look - I have visions of it being like taking the back off a watch with springs and bits flying everywhere

[Solarman]

First, there are several through bolts that bolt the entire assy to the side wall. Once removed there may be several separate access covers for different areas. Yes, there usually are some springs and balls in certain areas that might pop out if not careful. But, it isn't as bad as a watch. If the cover is spring loaded, it is keeping something in place. There are greased gears, levers, sliding parts, ball bearings and linkages inside, and some plastic pieces, as Harper mentioned. Plus a neutral switch, kill switch if mounted in control, and warning buzzer if inside, also wires for the trim tilt switch, and some controls have the key switch plus those wires. If you see the manufacturers name, model number, you might be able to look up online for a parts diagram/ schematic which might help you understand how it goes together.
There are many controls, and i'm not sure which you have, or what is included in your controls.

The only thing I can imagine that might hum, as I mentioned, would be the buzzer. If you were able to pull the buzzer outside the control box (wiring permitting) and take a test ride, it could tell you if the buzzer or still something else inside is your problem, might help you.

Good luck, keep us posted.

[Weymouth1]

Noise

Thank you guys
The weather is awful at the moment but I will venture into taking it apart as soon as the weather breaks
I will post back once I have worked it out