6V-12V question relating to 1956 Javelin

[bill-mcnamara]

When re-doing “The Twins” a few years ago, I changed the starter solenoid from 6V to 12V to be able use a 12V battery for easier starting.
Many hours of happy boating since.

For the electric choke I used an auto ignition resistor ballast to drop the voltage so I could use the original switch. Fast forward a few years and choke solenoid barely moves the choke linkages, and won’t close the butterfly plate, unless I nudge it with 12V momentarily.

The Starboard engine had become harder to start from cold last season. Now I think I know why…….non-functioning choke.

I realize that I could hobble over the bench seats and pull the mechanical choke, but I’d prefer to have the e-choke fully operational.

Question: I was wondering if I could just use a skip wire around the ballast or remove it all together, and feed 12V directly to the 6V switch and not have it blow?
It is only activated for a couple of seconds at the beginning of the day.

Another solution might be to harvest a couple of 12V choke solenoids from some ’57 and later RD’s that are resting in my barn.

I would appreciate and comments, suggestions or experiences in this area.

Bill.

[frankr]

I guess i would first measure the voltage at the choke as it is now. Maybe it is less than 6V

[bill-mcnamara]

Thanks Frank, good place to start.

Couldn’t do that today as I was working solo at the time.I’d need a buddy to depress choke button up at the dash while I take a measurement at the engine….wouldn’t I ?

How about skipping 12V directly to ballast and see what I get at its output side, or at the switch?

Bill.

[frankr]

Either one sounds ok to me. It all boils down to a matter of voltage drops and where.

[outbdnut2]

Since it was working and now isn’t – something changed, and you should find out what. If you don’t correct the problem it will likely just get worse bypassing the resistor if the resistor itself is not the problem. It could be any of the following:

1. Ballast resistor resistance increased.
2. Resistance increase of cable ends anywhere there is a connector crimped or soldered on the end of a wire.
3. Loose or corroded terminals at wire ends.
4. Choke push-button switch contacts getting pitted with age, giving the contacts resistance (Try shorting the wires together that connect to the back of the switch and see if the choke works).
5. Termination of internal choke solenoid winding wire at solenoid terminal gone bad increasing resistance.
6. The choke solenoid could have internal short(s) in its coil windings, which will cut down solenoid efficiency, and draw more current, causing more voltage to be soaked up by the resistor.
7. The moving actuator parts of the choke solenoid and/or the choke on the carb itself are gummed up or binding, needing more energy to close the choke.

Note that the resistance of the resistor you added should be the same as the resistance of the choke solenoid coil, so it soaks up half the voltage (soaks up 6 volts). Odds are it’s not the correct resistance, because automotive ballast resistors are sized to soak up half the voltage with an ignition coil load which is different than your choke solenoid load.

Easiest way to check if you have the right resistor is to put a voltmeter across the resistor and you should read half the battery voltage (6 volts) when you push the choke button. If you are a ways off 6 volts, either the resistor is wrong, or the choke solenoid coil has developed shorts or high resistance termination at the coil wire ends.

If you troubleshoot with an Ohmmeter, you will need a meter that reads accurately at very low resistances.
Let us know what you find!
Dave

[bill-mcnamara]

Dave, Thank you so much for your extensive reply, much appreciated.
You gave me several good ideas and leads.

I did have success yesterday afternoon, when I discovered the rubber boot on the actuator may have been been causing some interference, because it seems to be working as in previous seasons now.

I then moved over to the Port engine and discovered the same very lazy behavior of the 2nd solenoid, too weak to actually deploy the choke from the dash switch.

Heading out to the garage, coffee in hand, to continue the investigation.

Thanks again, Bill.

[crosbyman]

try a shot of a common release agent on the plunger… wd40, release-all etc… silicone spray

Joining AOMCI has priviledges 🙂

[bill-mcnamara]

Thanks crosbyman, I Had already used Seafoam “Deep Creep” on both mechanisms.
I think that may have helped getting the starboard choke operational.
Still no luck Port side.

As per Dave’s earlier suggestions,

1) I did use a skip lead on the dash switch, no different effect in performance.
2) I measured the voltage across the ballast resistor while depressing the dash switch,
and got 7.8V.
3) I also measured voltage to the power terminal at the rear of the solenoid while depressing the dash switch, and noted 3.5V ???

I repeated the measurements on the other (working) solenoid, and got exactly the same readings.The only difference being one choke works, the other doesn’t.
Confusing to me.

To my mind, 7.8V across the resistor should provide enough voltage to operate the solenoids well,
I do not understand the 3.5V at the solenoids though.

Both solenoids perform beautifully when 12V is momentarily supplied.

Thanks to all for comments and suggestions.

Bill.

[frankr]

What this is telling you is that the resistor is DROPPING or reducing the voltage by 7.8 Volts. In other words, 12 Volts minus 7.8 Volts equals 4.2 Volts available at the solenoid. Your reading of 3.5 leaves 0.7 Volts being lost somewhere else, which can be meter error or just resistance in the rest of the wiring, or whatever.

Bottom line is your resistor is too high an Ohms value.

[bill-mcnamara]

Frank,
Last evening I realized what the readings were telling me.Thanks for the conformation this morning.
Temporary (hopefully) brain-cramp yesterday.

Now have to source more suitable resistors, any suggestions?

Bill.

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