Fuse blowing

[French Tickler]

Hi all. I've converted my 1954 H van from 6volts to 12 volts, new alternator, lamps, coil etc. Plus new 12volt starter solenoid. My problem is that there is a direct live to earth at the coil. So when I push the starter button, the fuse blows. I have traced this to the coil side of life.
Put a meter on the neg side of the coil & to earth & open the points, no earth, close points, earthed.
All that's in this circuit is out going side of ign. switch to starter button--starter button to solenoid.
out going side of ign. switch to + side of coil, push starter button & blows fuse--------what am I missing here please?

Oh, if I direct feed from battery to outgoing side of starter, she fires up & runs, so I'm thinking the coil is ok, or am I wrong?
Should the condenser wire, which is connected to the dizzy along with the neg wire from the coil be insulated, should the whole neg side of the coil be insulated---straw clutching now.

[RichardW]

No idea...can't follow it. Need a wiring diagram that shows which fuse! Presume it worked before on 6V?

[dnsey]

Why is the coil connected to the starter button? They're different circuits.
The coil is permanently energised via the ignition switch when running, but the starter solenoid is powered via the button only when starting.
Do you mean that the starter button and coil share a live feed from the ignition switch? If so, the fuse and wiring need sufficient capacity for both circuits. The new coil and solenoid will probably draw more current than the 6V ones, so you may well have to upgrade the wiring - DON'T just fit a bigger fuse, which will be a fire risk. It may be a good idea to use a relay to control the feed too, to avoid possible damage to the ignition switch.
It used to be considered bad practice - 'coil-robbing' - to drive anything else from the coil circuit as the coil voltage could be compromised under adverse conditions. It would be better to take a complete new supply for the starter.