Ignition Switch Question

[BadBahner]

I am doing a bit of a rewire on my new boat I bought and I found something wierd. Going into the ignition switch I get 12.60 vdc. Coming out (When ign is turned on) I get 10.56 vdc.
The boat starts... everything works except the volts gauge reads 10.5. Could the ignition switch be jacked up inside or is it supposed to do this. :cry:
Hmmmm
Thanks
Eric

[Oldsquirt]

If it showed that while cranking, I'd say it is OK, but if that is just "key-on" it's not good. Have you checked the voltage at the B+ terminal of switch with key on?
Next test. Connect voltmeter positive lead to the B+ terminal of switch and the negative to the "Ign" terminal. Turn key on and read meter. tell me what you get.
If the boat starts and runs, what is the voltage AT THE BATTERY?
What sort of rewiring did you do?

[BadBahner]

I bought all new gauges and I wanted the underside of the dash to be really clean. So I am rewiring the 12v and Ground but using existing signal wire. It was quite messy under there. I am assuming the B+ terminal is where a wire would be attached to on the keyed ignition switch and deliver power to the gauges when the key is in the on position. I have not messed with cranking the engine.
Voltage at the battery is 12.6vdc
Thanks,
Eric
If it showed that while cranking, I'd say it is OK, but if that is just "key-on" it's not good. Have you checked the voltage at the B+ terminal of switch with key on?
Next test. Connect voltmeter positive lead to the B+ terminal of switch and the negative to the "Ign" terminal. Turn key on and read meter. tell me what you get.
If the boat starts and runs, what is the voltage AT THE BATTERY?
What sort of rewiring did you do?

[Oldsquirt]

B+ is the power feed TO the switch.
Ign is the circuit that comes on and feeds ignition and gauges.
Start(S) is kind obvious.
Do you run a voltmeter in the dash or an ammeter?

[Hemicbx]

BadBahner,
Seperate but related issue:
I was continually blowing fuses last year until I finally got to the ignition switch. Cured everything. It's a simple little piece but can ruin a good day. For the cost of a new one, I'd do it if there's any doubt.
Hemicbx

[BadBahner]

B+ is the power feed TO the switch.
Ign is the circuit that comes on and feeds ignition and gauges.
Start(S) is kind obvious.
Do you run a voltmeter in the dash or an ammeter?
Voltmeter in the dash. I hooked it up directly to the battery and it reads correct 12.6
OK Ign reads 10.5 and B+ Reads 12.6
I am trying to avoid replacing the ignition switch but it looks like I am going to need to do that.
Eric

[Oldsquirt]

HemiCBX, that's why I wanted him to do the voltage drop test between B+ and IGN. Had one early this year in a friends boat. Voltage drop between B+ and Start was 8 volts! Can you say "click, click" ? I autopsied the switch and it was a fried and corroded mess. It was supposedly a 1 year old switch. It was definitley a "cheapie"
http://www.hotboatpics.com/pics/data/500/3633Brenda_sSwitch2.JPG
http://www.hotboatpics.com/pics/data/500/3633Brenda_sSwitch1.jpg

[Oldsquirt]

BadBahner, do this test exactly as it is written. Bring back the result..
Connect voltmeter positive lead to the B+ terminal of switch and the negative to the "Ign" terminal. Turn key on and read meter. tell me what you get.
OK Ign reads 10.5 and B+ Reads 12.6
The difference between the two is the "voltage drop" through the switch. In this case 2.1 volts. The allowable through a switch is generally 0.2 volts.
If you ran the test my way, you would be measuring it directly rather than in two steps plus a little math.
You need a new switch and they're only about $25-30. Buy a "Cole-Hersee" available at West Marine or from Rex Marine. The one pictured above is the "cheaper" of the two sold through West.

[BadBahner]

BadBahner, do this test exactly as it is written. Bring back the result..
Connect voltmeter positive lead to the B+ terminal of switch and the negative to the "Ign" terminal. Turn key on and read meter. tell me what you get.
The difference between the two is the "voltage drop" through the switch. In this case 2.1 volts. The allowable through a switch is generally 0.2 volts.
If you ran the test my way, you would be measuring it directly rather than in two steps plus a little math.
You need a new switch and they're only about $25-30. Buy a "Cole-Hersee" available at West Marine or from Rex Marine. The one pictured above is the "cheaper" of the two sold through West.
I just made the trip to west marine and I am installing the new switch now.
Eric