I started with manifolds and ended up having to remove the mech. pump on my 454 powered outlaw.

I'm pretty sure that purple is the standard "switched" hot lead throughout the boat but can I tie right into it, or do I have to run a relay?

My pump is a standard holly red pump that draws aprox. 7.5 amps max.

Any ideas? please help

I have mine on a relay

Absolutely, put it on a relay.... and fuse the relay & the pump seperately.....

You want it on a relay and the power lead direct to the battery.

What is the advantage of running it off of the relay as compared to the switched wire?

off of the relay will give you an individual circuit just for the pump where as the switched wire it will be on with whatever is switched[gauges, halon etc.] could be a lot of stuff . you also might want to put that on a toggle as well .

It's done thanks everyone for the help.

This will be much better than the way I had it rigged to a toggle switch, I kept forgetting to turn off

Does merc have any safety shut down in there systems?
Like a temp sensor or oil pressure sensor that would shut down the ignition?

I have mine wired using a relay. I powered the relay off the ignition circuit. When the ignition is on, the pump is on. This has a benifit that when the kill switch is pulled, the fuel pump is also shut off. The pump will pull around 7 amps. Not a significant load, but enough that it will compete with the ignition system. The relay takes the load off the ignition circuit and puts it on a nice powerful source.

Fusing the pump is always a good idea.
Carter does recommend that you install an oil pressure switch with their marine electric fuel pump.
The switch is one eighth NPT thread and can be installed on the back of the motor by installing a tee fitting where you sense oil pressure.
The switch basically has three male spade terminals on it, one wire goes to I ignition, the other goes to the S started solenoid so when your cranking engine with no oil pressure it will energize the fuel pump, once the motor starts and senses oil pressure the pump will stay running. And the third wire goes to the P pump.
The STANDARD PART NUMBER FOR THE SWITCH IS PS64
I think you need to install the switch as a safety precaution, if you loose oil pressure it shuts off the pump, or if you stall for any reason you do not have the pump working.
Good Luck
Brian

I think it is a Coast Guard reg that the electric pump has to shut off when the engine is not running. Do a search on coast guard fuel systems.

I could send the file but I just got a new computer and all that stuff is still in the old one. I'll try to search it, too.

Bulldog aka Ronnie