|Used to put Delco Distributors into service mode for timing carbureted and EFI engines.
Instructions: Remove 4 pin connector from base of the distributor and install timing tool in it's place. For carburetd engines Start engine and then connect the single wire to a 12 volt source. Set timing to 10 Degress BTDC, disconnect from 12 volts and reconnect original distributor plug. Reset idle to 750 rpm.