Best places to tap for fuel pump?

[duped]

I have all but completed an engine swap into my boat. The engine is newer and does not have provisions for mech. fuel pump. All other marine related parts/harness are transferred from the old motor (1986 merc 305). I have purchased a nice carter marine electric fuel pump, and also a oil pressure switch with 3 pins...

P (to pump)
S (from starter solenoid to give pump power during cranking)
I (ignition...hot in run)

My question is, what are the most convenient wires to tap for the solenoid and ignition? This is a Thunderbolt IV system.

I believe the solenoid wire is yellow w/red stripe...is that the one I want?

And also, what's the best one to tap for ignition? Positive on the coil?

 

[alldodge]

Re: Best places to tap for fuel pump?

I have all but completed an engine swap into my boat. The engine is newer and does not have provisions for mech. fuel pump. All other marine related parts/harness are transferred from the old motor (1986 merc 305). I have purchased a nice carter marine electric fuel pump, and also a oil pressure switch with 3 pins...

P (to pump)
S (from starter solenoid to give pump power during cranking)
I (ignition...hot in run)

My question is, what are the most convenient wires to tap for the solenoid and ignition? This is a Thunderbolt IV system.

I believe the solenoid wire is yellow w/red stripe...is that the one I want?

And also, what's the best one to tap for ignition? Positive on the coil?

You should use the purple/yellow stripe going to your S connection (that is unless you do not have this wire the yes use .Yel/red stripe) The solid purple wire will go to the I connection. This is assuming, P is Common, P is normally open, and I is normally closed on your oil pressure switch.

 

[Bondo]

Re: Best places to tap for fuel pump?

I have all but completed an engine swap into my boat. The engine is newer and does not have provisions for mech. fuel pump. All other marine related parts/harness are transferred from the old motor (1986 merc 305). I have purchased a nice carter marine electric fuel pump, and also a oil pressure switch with 3 pins...

P (to pump)
S (from starter solenoid to give pump power during cranking)
I (ignition...hot in run)

My question is, what are the most convenient wires to tap for the solenoid and ignition? This is a Thunderbolt IV system.

I believe the solenoid wire is yellow w/red stripe...is that the one I want?

And also, what's the best one to tap for ignition? Positive on the coil?

Ayuh,... Generally speakin', for Power, while crankin' on the starter, the starter's solenoid, is tapped on the Outboard tiny terminal,...
It's a more direct link to battery voltage than the red/ yellow terminal,...

For the Run on the Ignition, All the purple wires on the motor are the Ignition circuit, 'n the electric choke is a common tap point,...