Vintage Cars: Austin Healey 100/4, healey starter solenoid

Question
Hi,
My 1953 Austin Healey runs great, BUT just this week the starter is sticking.  Upon ignition it cranks and fires up with no problem but continues to whine.  Haven't driven it, I'm only able to turn it off my turing the battery switch off in the boot.
Once I turn the battery switch back on, it's cranking again even without the ignition key turned on.
Help.

Answer
1953? I'm jealous!

I don't know the car (naturally, given the rarity), but will assume that you have a button on the dash and a solenoid low on the engine bulkhead, right side, near the starter. I think your solenoid is stuck closed (i.e. on). Starter power comes directly from the battery through the solenoid, so if it's stuck, switching off the ignition (that's the small wire on the solenoid) will have no effect. The unlikely alternative is a sticky starter button on the dash. But I forget whether that is always live, or powered via the ignition switch. If the latter, a sticking button can't be the cause.

Try gently whacking (!) the push button on the solenoid (the rubber cap), and also the side of the solenoid, with a wrench. If that temporarily cures it, I suggest a new solenoid. Actually I suggest that in any case. They're not expensive (Moss or Victoria) and easy to install.

Jo Jesty