Pontoon won't start suddenly

Shadow_Vampyre

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Jul 15, 2019
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I have a Bentley pontoon and it worked fine 2 weeks ago when i took it out of the water on my trailer. Today, I went to test start it in my backyard, and no beep, no click, no gauge activity, nothing.
The accessories work(horn, lights, radio) and I put a meter to the battery, it is 13.8 volts. I keep the battery on a trickle charger as well. I checked the safety lanyard, it is fine. Looking under the helm is a mess of wires, and i saw 3 fuse holders, all had good fuses. There might be more, but I can't seem to find them.
I was thinking it might be a switch problem, i reached up inside the helm, nothing felt loose. So last time everything was fine, loaded on the trailer for the day, and here we are. Now it sat uncovered for the two weeks (unusual, normally i cover it) and it got rained on with the key in the ignition (like i have before to no ill effect) in the off position.
The odd thing is back on the engine, the power tilt up and down rocker buttons does nothing, no noise or anything. This kind of makes me think it is not the key/switch now.

Does anybody have any ideas? I am at a total loss and this is very frustrating as I had the family ready to go out tonight.
Thanks,
Chris
 

mike_i

Master Chief Petty Officer
Joined
Jun 28, 2017
Messages
879
Something may have finally corroded thru to the point of having an open circuit while sitting. Did you measure the voltage on the back side of the key switch? If you have juice there what about the starter while trying to start it? Do you only have one battery? Do you have any battery disconnect switch?
 

Shadow_Vampyre

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Jul 15, 2019
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I have no battery disconnect switch, and one battery. I have not tried voltage on the back side of the switch yet, possibly today, will have to disassemble the dash, its hard to get at anything
 

Silvertip

Supreme Mariner
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Sep 22, 2003
Messages
28,758
I will assume this Bentley has an outboard motor. If so, check the fuse under the engine cowl.
 

Shadow_Vampyre

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Jul 15, 2019
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I cleaned the battery terminals, battery was new last year, so already clean. Found a master fuse 20 Amp, it looked good and had power to to it, was right next to battery.
Took apart dash, switch harness has no power going to it.Looked under the boat, did not see any problems with wiring.
Motor local tilt function still not working, took off engine cover, no fuses here.
I am at a loss.
 

GA_Boater

Honorary Moderator Emeritus
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May 24, 2011
Messages
49,038
What motor? Some hide the fuses.

Accessories work and nothing else - No crank, gauges or TnT. There are 3 circuits involved;

Accessories are powered by from the battery, probably through the 20A fuse.

Gauges and starter are powered through the key switch.

TnT is isolated electrically and always hot. It should work regardless of the key switch.


Flying blind without knowing what motor.
 

GA_Boater

Honorary Moderator Emeritus
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May 24, 2011
Messages
49,038
Mercruiser 90

What in the world is that?

The odd thing is back on the engine, the power tilt up and down rocker buttons does nothing, no noise or anything.

If it's a Mercruiser, the above makes no sense. Some outboards have TnT switches on the cowl, but I/Os don't have them on the motor.

Let's try again and throw some light on the shadows - Is it an outboard or I/O and exactly what? Bentleys come both ways.
 

Shadow_Vampyre

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Jul 15, 2019
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SOLVED!!!! There was a 15 AMP fuse blown under the engine cover. The manual says it is for the helm/ main power relay! Replaced it and power trim works (local and remote), engine starts, beep on key turn, etc.

Thank you to all who helped!
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
You have a Mercury outboard -- not a Mercruiser which is an I/O. Keep that in mind if and when you have to order parts. Also just for future reference: When you have to troubleshoot electrical problems, ask yourself "is this engine related or boat related. Boats have two basic electrical systems. One for the engine which is the big harness that runs from the engine to the shift/throttle control box. The other is the "boat" system which is the harness that runs from the battery to the switches, gauges, and other accessories.
 
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