Re: 1956 Johnson Javelin wiring harness help needed please

[David Stanton]

I believe someone sold you a 6 volt Ford starter relay (for 1954 and earlier Ford cars) which looks about the same and would work exactly as you described, requiring the mount to be grounded. Note that grounding of the mount bypasses the safety function of the Mercury switch.

FYI: Sierra/NAPA sells 12 volt replacements but not 6 volt, and these have two small terminals – one goes to the Mercury switch and the other gets its signal from the starter switch. If you decide to go with a 12 volt system, which I highly recommend – you will get much faster starts and you do not have to change the starter, just add a resistor in series with the choke solenoid – use same resistance as the choke solenoid coil and enough wattage rating to handle it. For a resistor in this application, Watts = 36/R. where R is resistance. Go at least a watt or two over the number you calculate.
Dave