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Old 12 May 2011, 06:40   #1
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Engine noise through VHF

Our VHF is perfectly audible until you start the outboard. Is this likely to be a bad earth or do I need a noise suppressor?
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Old 12 May 2011, 06:54   #2
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Might be a difficult one to solve. I've had an outboard which appeared to transmit from the ecu. It was intermittent but no amount of fiddling solved it. I've a similar problem with my current engine, its occasional and only after hours of running and also only on some channels. Switching off and restarting doesn't solve it but running with the ignition off does. I wish you good luck.
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Old 12 May 2011, 06:58   #3
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Is it a 2 stroke?
if so do you have the corect plugs. ?
what sort of noise are you getting?
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Old 12 May 2011, 07:03   #4
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Quote:
Originally Posted by jezza2011 View Post
Is it a 2 stroke?
if so do you have the corect plugs. ?
what sort of noise are you getting?
Yes it's a 2 stroke, with the correct plugs. It's a constant buzzing sound.
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Old 12 May 2011, 07:24   #5
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Can you use a handheld and see if that has the same? That will tell you if it is a transmission or a wiring issue.

If the handheld does get it try taking the antenna out and seeing where the noise is most clear, that might help to narrow down the source.
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Old 12 May 2011, 12:12   #6
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Common things to try:

If possible, route VHF coax away from the wiring loom coming from the motor.

Try jumping engine block to negative battery terminal with a heavy piece of wire. Noise reduction points to bad grounding.

Re-terminate the PL-259 connector on cable.

Try a resistor spark plug of similar temperature. Should cut down on spark interference.

Try running VHF from a separate, isolated power source while running the motor. If that fixes/reduces noise, it points to a grounding problem.

Luck;

jky
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