Triumph Repair: GT6 MkIII coil/ballast question, starter solenoid, haynes manual

Question
Hi Howard. Thanks for all of your past answers to other folks -- they've been quite a help in sorting out some minor problems with a GT6 I recently purchased.

I've been having what I think are ignition issues. The car drives great, but when I get on the highway, at about 3000 RPMs the engine starts missing. I've got new points, condenser, cap, and rotor coming in the mail. And I've replaced the plugs and wires. So I'd like to also put in a new coil. Which of course brings me to my question.

I have a later GT6 with the ballast wiring, rather than the resistor. I'm pretty sure that I have a 6V coil -- it shows 6.4VDC with the ignition on, and about 9.2VDC when I crank it. But as I've been going through the wiring, I've become a bit confused.

The previous owner replaced the starter solenoid. In my wiring diagram (Haynes manual), it shows a white/yellow wire coming off the solenoid which connects to the (+) coil, and the ballast. A white/red wire connects to terminal 1 of the ignition switch. On my solenoid, the white/yellow wire is unconnected -- in fact it appears that the terminal it should connect to on the solenoid is gone entirely (though it appears to be an almost brand new unit). Using a VOM, I can't seem to figure out what that wire connects to. And the white/red seems to connect to the (+) coil instead.

As I said, the car runs fine, starts up easily with a manual choke out. I just get mildly concerned when I run into what seems to be non-standard wiring like this. I'd also like to be sure that I'm buying the right coil.

Thanks for any assistance you can give.

Answer
Hi Nathan,
Your car uses a 6v coil and a resistor wire to power it when in the Ign position. When in the Start position it uses a White w/yellow tracer wire from the starter solenoid to bypass the resistor wire to apply 12v to the coil.

If your car has been starting ok without the solenoid supplied 12v then I would not worry about it but do tape up the wire at the solenoid so it does not short on anything. If the car gets hard to start in the winter you may have to get the correct solenoid and connect the wire back up.

Yes, you must use a 6v coil.

Howard