on the merc schematics a oil pressure switch is shown from + side of coil to electric choke I am assumintg that this activates choke and takes power off when it see oil pressure is this correct and since new carbs have no choke I am also thinkink I dont need this switch

Do you have an electric fuel system? I have an oil pressure switch that removes power from my fuel system (via a relay) in the event of oil pressure loss. It's saved me twice from serious engine damage.

Another option would be to switch off power to your coil if you loose pressure.

IMHO, you do need this switch, but maybe not the way Merc intended in their schematics.

Brian

The switch applies 12 volts to the choke heater when oil pressure comes up. If you no longer have chokes, it becomes superfluous. Just make sure it is only a 2 wire switch and not a 3 wire if you choose to delete it. If its a 3 wire, leave the switch in and just tape off the wire to the choke.

From the schematic I was asssuming that was the way it worked not sure why merc did it that way rather then applining power to it when the key was turned on I guess it was a saftey of some sorts