Crest Pontoon radio speakers shutting off when throttling up motor???

[3chap0]

My son has an older Crest III Pontoon boat with a 60hp Merc. bigfoot on it. When throttling up the motor in forward, for some reason it kills the speakers on his radio in the boat. When in nuetral, it doesnt affect the radio. Then he throttles back down and sometimes they come back on, but if they dont, he puts it in nuetral and throttles up and down, and they come on. Weird I know!! But I thought there may be something in the throttle housing that switched the speakers off?? It is a new marine radio, but his old radio did the same thing. When in forward gear, the speakers die at about 3000 RPMs. Its just the speakers, the receiver stays powered up... If any suggestions, I would appreciate it....thanks

 

[Silverbullet555]

Re: Crest Pontoon radio speakers shutting off when throttling up motor???

All I can think of is a loose wire or broken wire that is losing contact when the boat starts to vibrate at a certain rpm. I would run new speaker wires and see if that fixes it.

 

[Silvertip]

Re: Crest Pontoon radio speakers shutting off when throttling up motor???

How old is the motor? If the charging system is unregulated, system voltage goes too high and the Over-voltage protect circuit in the radio turns off to protect the radio. What does the voltmeter on the console read at higher engine rpm. If there is no voltmeter, check the voltage with a handheld multi-tester (volt, ohm, milliammeter) available at any home improvement store for less than $15.00 and a valuable diagnostic tool for any boat owner (provided one learns how to use it).

 

[3chap0]

Re: Crest Pontoon radio speakers shutting off when throttling up motor???

Thanks for the replies. Not sure how old the motor is, would guess 80's model. Dont know about the charging system for sure, but there is still power to the radio, with the display still lit up when speakers go dead. If the voltage does get to high on Over-voltage, wouldnt it kill the display lights on the radio too? The voltmeter on his dash is showing it is charging the battery. I'll see if I can round up a voltmeter, to check this out too....

 

[Silvertip]

Re: Crest Pontoon radio speakers shutting off when throttling up motor???

The display is less voltage sensitive than other critical circuits so no -- the fact that the lights stay on means nothing other than there is power into the unit. It is the internal circuitry that is being protected. You won't know what the issue is until you check system voltage with the engine running. Even if the engine has a regulator, it may be bad allowing the over voltage condition.

 

[3chap0]

Re: Crest Pontoon radio speakers shutting off when throttling up motor???

Thanks, but what gets me is, he can put the motor in reverse and rev it up, and the radio still works. Its just happening in forward gear when getting up over 3000 RPMs. I will have to brush up my skills on the multi tester. I think your exactly right about the radio having an internal protection that shuts it down, but display is showing just power to the unit. (stupid question) - Can I just hook the meter to the battery to check the system voltage when running? Sorry for rookie questions.....

 

[Silvertip]

Re: Crest Pontoon radio speakers shutting off when throttling up motor???

Yes - that is the power center. Put the probes on the battery posts -- not the terminals