Spitty starter solenoid.

[jockney49]

Hi. Can anyone help with Spitty mk4 starter solenoid. First thing is how to test it. Workshop manual does not cover testing of this item. Also need confirmation of wiring for the white/red wire and white/yellow wire. There is one small spade connector on the body of solenoid. The other small spade connection is part of a large spade directly underneath top screw connection. Which way round are small wires connected ? Battery tests ok, starter tests ok and ignition switch tests ok. All connections have been cleaned. Only solenoid condition left to confirm i think. Thanks in advance. James. P.S. This is not fitted with separate ballast resisitor. Has ballast resistor wire on loom.

[bodders1]

Hi James

Testing the starter solenoid:  apply +12v to the connector used for the white/red wire the engine should crank over (or, at least, you should hear a satisfying clunk from the solenoid.

The most common cause for solenoid "failure" is losing its earth connection.  The return path for the actuating current is through its mounting bolts and into the bulkhead.  If you have corrosion in the mounting bolts, or if you have just repainted your bulkhead, then the solenoid may have a poor earth and appear to be broken.

Identifying which terminal is which: In addition to the big wires going to battery and starter motor, there should be one or more brown wires connected to the same big terminal post as the battery.
That should leave two small connectors.  One operates the solenoid, and should be connected to white/Red wire from the ignition switch.  The other small connection is for the White/Yellow wire which goes to the +ve terminal of the ignition coil.   If you have a multimeter, you can check which is which by measuring the continuity as follows:  the connector for the White/Yellow wire should be permanently connected to the large terminal post going to the started motor.  The other connector (white/red) should have a low resistance connection to the solenoid body (this is often too small to be measured as a resistance and will appear as a direct connection when measured with a multimeter - don't worry, it is not a short circuit, it is the lowish internal resistance of the solenoid coil itself).

hope this helps.

[Paudman]

Alternatively just do what I do which is to take reference photos from properly setup Spitfires so that when the brain fails late at night I have a good illustration of how things should look!
Saves straining the eyes on a workshop manual!
Colin

[junkuser]

The lonely little spade is the one that actuates the solenoid.
If you momentarily flash a wire between this little bloke and the big spade with the little mate the solenoid should jump into action.

If this does not stimulate the starter motor to awaken then the contacts within the solenoid are most likely too burnt away or rust may have developed in the solenoid, jambing the slug.
These are the only two faults I have encountered with Lucas solenoids but there could be others

[junkuser]

On aftermarket solenoids you may find two lonely little spades.
These don't actually talk to each other.
One does the same job as on the old Lucas but the other communicates with the main terminal from the battery and talks directly to the coil when the other little spade is stimulated, ignoring the ballast resistor if one is fitted.
These terminals are often not labelled so you have to use a meter or apply power to identify.
I'm not sure if "spade" is politically correct these days.