Thank you Aussietrev for your quick reply and information. With battery and solenoid located in the rear of the mower, I'll track which wires are going where before doing any of the rewiring. Will connect the earth return from the starter to the small post and change the bayonnet fitting to a post fitting. Other three post solenoids, which are at the front of a mower, normally have the main battery earth going to the smaller terminal and another from the ignition to the negative battery terminal (I think I got that the right way around)....
Appreciate your assistance.
Regards
Daryl
