Nav and dash lights too dim

[morganhudgens]

I just picked up a 1993 32' SunTracker Pontoon with a 1996 Johnson 150 outboard. Last night, on the lake, the green and red nav lights, as well as the white in the back, all began to dim, until they were virtually un-seeable. The dash lights were also so dim that you couldn't read any of the gauges. I have always had an I/O motor, and understand that the alternator powers the electronics while running. Does an outboard motor operate the same? Shouldn't it be generating power for the lights, dash, radio etc? The boat does have a separate generator for the cabin, but I understand that it powers the fridge, stove, AC, etc... when in use. None of that was on. Just the nav lights. It was almost like the alternator was not charging, and the battery was losing juice during the trip until the lights went out.

 

[Grandad]

Re: Nav and dash lights too dim

It was almost like the alternator was not charging, and the battery was losing juice during the trip until the lights went out.

That's what it sounds like to me. Was the starting battery dead after this happened? A gradual progressive dimming indicates a gradual loss of power that poor connections wouldn't account for. - Grandad

 

[morganhudgens]

Re: Nav and dash lights too dim

The starting battery was not dead this morning when I went out to start the boat. Turned right over and started, although after sitting all night, it would have recharged itself a bit, and the motor starts rather easily, so didn't have to use much battery. When the motor is running, the volt meter on the dash shows charging. I just don't understand why the nav lights would dim like that. Anyone else got any ideas?

 

[gm280]

Re: Nav and dash lights too dim

Well your gauge may show a charge but not much current being replaced. So there is either a faulty wire (corrosion, loose, needs retightened, etc) OR your rectifier is not working properly. No other reason for dimming lights as you are running. Lights don't really pull that much current, but if the battery is not being replenished it will drain down and if you continue running with it that way, sooner or later your engine will probably stop too... If your engine is using the same battery to run the ignition...

 

[morganhudgens]

Re: Nav and dash lights too dim

Thanks for the reply gm280. Can you advise me as to how to check the output of the rectifier? Obviously, I can check the connections at the battery, and if it was in I/O, I would know how to check the connections at the alternator, but with an outboard, I'm lost. Any advise and direction would be greatly appreciated.

 

[gm280]

Re: Nav and dash lights too dim

Thanks for the reply gm280. Can you advise me as to how to check the output of the rectifier? Obviously, I can check the connections at the battery, and if it was in I/O, I would know how to check the connections at the alternator, but with an outboard, I'm lost. Any advise and direction would be greatly appreciated.

Do a simple search here on these forums for "How to test a rectifier". There is very informative step by step instructions to help you test your rectifier. Then you will know for sure if that is your problem or rule it out!

 

[boobie]

Re: Nav and dash lights too dim

The only time you use the battery for the motor is to start it. The ignition is self contained.