Dashboard electrical problem

[hitest1024]

Hi-
I have a 1985 Bayliner Capri (19.5 foot).
I was out enjoying a great day on the lake sunday, when I stupidly decided to to try to diagnose an occasional start problem. (Sometimes you would have to giggle the bottom of the fuse panel before it would turn over- just got the boat 4 weeks ago.) In feeling along the fuse box (under the instrument panel) I felt that one of the connections was burning hot... Anyway, it was easily accessible, so I pulled it off, crimped the connector a little bit and reconnected. I was conscious of not disturbing anything else, but...

It would crank, but not turn over. All instruments were dead, although the bilge and horn worked. (All was working before.) It behaved exactly as if the 'on' position on the ignition switch wasn't working. I took a spark plug wire off (the spark plug end) inserted a screwdriver and set on the valve cover while cranking, with about a .5 inch gap. No spark.

I've got the wiring diagram and have studied it till I'm blue. I'm going to go back up there tomorrow with my voltmeter, a big light and the wiring diagram, but if anyone had any thoughts at all, I would be grateful.

As for my mechanical ability, I do almost all of my own car repairs, have replaced my own transmission, and have wired up light circuits in my home, but I do not have a good track record with this sort of electrical gremlin... So again, any advice is welcome. Thanks very much.

 

[Silvertip]

Re: Dashboard electrical problem

First lets clear up some terminology. Crank and turn over are the same thing. Crank and turn over means the starter is spinning the engine but it is not starting. There is a "B" terminal, an "S" terminal, and an "I" terminal on the ignitioin switch. B=Battery which is +12 volts from the battery via the engine harness. S=solenoid as in starter solenoid. When you turn the key to START current flows from the B terminal to the S terminal to energize the starter solenid which cranks the engine. I=ignition which feeds +12 volts to the ignition system. You need to check for voltage on each of those terminals. There is also a fuse or circuit breaker at the engine that you need to check. If thats tripped or blown, you have no current to the B terminal and hence no start. But since the engine cranks, that doesn't seem to be the issue. If you have no spark, you likely have a problem in the ignition circuit (the "I" terminal I mentioned). And since the gauges are dead, you will need to look at the "A" terminal as well which is active in the run position of the key. This terminal feeds the gauges.

 

[hitest1024]

Re: Dashboard electrical problem

First off- thanks for the quick reply, and of course you're correct about the terminology... It was cranking and turning over, but not catching/running.

I think you're right that the 'S' terminal isn't the problem.

Three further questions:
What is the 'A' terminal that you mentioned? I'm guessing that its further downstream from the 'I'?
Where should the wire from the 'I' terminal go? (I don't have the wiring diagram in front of me, but I'm guessing it becomes the input to the fuse panel?)
Is it standard on these boats to have a ground panel close to the fuse panel? I didn't see one under the dash, and had to assume that black wires were ground. (Since confirmed by wiring diagrams.)

Thanks again.

 

[Silvertip]

Re: Dashboard electrical problem

The "I" terminal is the "ignition" feed for the ignition system and has absolutely nothing to do with the fuse panel. All engine related circuits -- that means all of the wires in the engine to control box harness are protected by a fuse or breaker at the engine. It's the boat harness that feeds the fuse panel directly from the battery (the smaller pair of wires from the battery). I suppose I should have asked earlier, and you should have provided this info -- but you boat is an I/O is it not?? I explaiined what the "A" terminal was. It is the "accessory terminal which feeds the gauges when the key is in the run position. If you measure 12 volts on that terminal when the key is on it is doing what it supposed to do. That terminal is not downstream from anything. Anything you want to turn on and off the with key is fed by that terminal. All of these terminals are on the back of the ignition switch.

 

[hitest1024]

Re: Dashboard electrical problem

Yes- its an I/O, or sterndrive (the Volvo Penta 270d)...
So the I terminal (which I think should be purple according to the diagram) will run back to the engine.
And the 'A' terminal will run to the guages.
'B' is the power supply directly from the battery.
'S' is the wire that runs to the starter solenoid.
Thanks again.

 

[Silvertip]

Re: Dashboard electrical problem

"B" is +12 volts from the ENGINE HARNESS not directly from the battery via the boat harness. You have two electrical systems on a boat. 1) the harness that runs from the engine to the control box. +12 volts gets to the "B" terminal on the switch via the large battery cable that runs to the starter solenoid. From there it passes up the engine harness to the "B" terminal where is actually the INPUT to the ignition switch. 2) The boat harness feeds +12 volts and ground directly to the fuse panel although it sometimes passes through a master on'off switch on the helm.

All of the other terminals are OUTPUTS from the igntion switch. The "A" terminal means "accessories" so anything, including gauges that you want to turn on and off with the key must be connected to that terminal. Yes, the "I" terminal feeds +12 volts back to the engine via the engine harness. I don't have the schematic for your engine so I can't verify colors.

 

[J. Mark]

Re: Dashboard electrical problem

Good luck