Engine Starting Woes II

Jul 17, 2017
3
Beneteau 331 Belmont
I wanted to tack on to a post Kimelmore started recently about a Westerbeke that wouldn't start. I have a similar situation on a 2001 Beneteau 331 w/a 30B engine and the Captain's Panel. I turned the key and got the alarm for a split second and then in went silent. I thought the buzzer might have just gone bad, or maybe the switch. I pulled the panel and I had power at the switch and I even jumped the switch but nothing. I have power at the starter but nothing happens at all on the panel when I turn the key. The Captains panel has a test button and nothing lights up when I hit that either. There is power at the 20A breaker on the back of the engine but again nothing is happening when I push the button. It was running just fine a couple days before, although I had a similar problem a couple years ago that a mechanic couldn't find but it started working again. I thought maybe it was just a switch so I replaced that but no luck.

The one odd thing is that when I turn the switch (key) the power drops from every contact, at the switch, at the breaker, it reads zero and possible goes negative (the needle seems to move to negative but hard to tell). I looked for a ground fault by taking off the battery cable and bridging the pole and the cable to see if I got a reading and that was negative. I think there are some kill switches in the engine that shut it down when it over heats or pressure is off but not sure why they would kick in before it starts. Any suggestions would be appreciated.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
weird stuff like this ALWAYS requires a circuit diagram to diagnose. There are diodes in these circuits to make them work correctly and when one goes bad you can get a resistive short to ground. Power up the circuit via the key switch and the diode lives for a moment (buzzer sounds and then goes off) and then every thing stops working because you have a straight to ground connection via the diode. If it dies with no resistance (dead short) then the fuses and CBs pop, if it dies with resistance (resistive short of 2-3 ohms) then you get really weird stuff that makes no sense at all but lots of things don't work correctly, if it shorts open you get no indication till an alarm does not work when it should (engine overheat with no idiot light/buzzer). The diodes are in the ground side of the idiot light circuit and are generally in-line (wide spot in the wire wrapped with electrical tape).
Good luck
 
Jul 17, 2017
3
Beneteau 331 Belmont
I had a multimeter and the manual with the wiring diagram, but the devices on the Captains Panel are all interconnected and I there was no detailed breakdown of their relationships. There is a "Terminal Diode Assembly" which is a push connector bar with multiple diodes between the different connections. I ordered that and will give it a shot. I would prefer to diagnosis the problem rather than just replace parts hoping one works, but the Mac Race was this weekend so getting anyone out on Friday or for the rest of this week will be tough. Thanks for the tip, I'll let you know if the diode assembly works.
 

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NYSail

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Jan 6, 2006
3,048
Beneteau 423 Mt. Sinai, NY
Power at the panel but what about back to starter? Harness problems, old wites voltage drop?