starter wiring

J

juliolop

Seaman
Joined
Nov 3, 2015
Messages
65
fetch


Can somebody explain what function has the purp/yellow wire from the OIL press switch (the same to the fuel pump) coming to the starter?
 
S

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
That wire bypasses the oil pressure switch (runs the fuel pump) during starting, before the oil pressure builds and the oil pressure switch closes, which will then supply voltage from the ignition (run) switch to the fuel pump.
 
J

juliolop

Seaman
Joined
Nov 3, 2015
Messages
65
ok and...
in someplace I read the fuel pump starts when the oil switch closes reaching 11-15 psi, and that the water sep filter should be fill with gas for the initial starting period,
both scenarios are understood but why the bypass then?
 
S

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
So the fuel pump will run before the oil pressure builds. Yes the carb and filter may have sufficient gas to start the engine, but they may not. Running the fuel pump when starting assures that the fuel system is supplied. For a fuel injected engine it will assure that you have sufficient fuel pressure to start.
 
J

juliolop

Seaman
Joined
Nov 3, 2015
Messages
65
And do you know if the power in this line disappear once the key is out of starting position?
 
S

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
It does! There is voltage on that terminal only when the starter solenoid is energized.
 
Last edited:
J

juliolop

Seaman
Joined
Nov 3, 2015
Messages
65
One last thing, I just finished rebuilding my engine CID 305 vortec,
Now in the process of connect every wire of the harness
I have some black wires with round terminals in the branch of the harness going to the fuel pump
I know they're ground connectiins but I'm looking foe the best place to tie them,
Any sugeation? Pics?
Thanks
 
J

juliolop

Seaman
Joined
Nov 3, 2015
Messages
65
I'm also building a little box with gauges and ignition/starting switches to test engines out of the boat.
can anyone give me the Part Number for the male connector (the one that connect in the engine connector) ? or a place where I can get it?
thanks
 
achris

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
juliolop said:
And do you know if the power in this line disappear once the key is out of starting position?
Click to expand...

stonyloam said:
It does! There is voltage on that terminal only when the starter solenoid is energized.
Click to expand...



Not quite right. The terminal is not energised from the starter side, but once the oil pressure switch closes that wire DOES have power on it. Also worth noting, when you are using a remote starter switch, for testing compression for example, as soon as the oil pressure switch closes (oil pressure reaches 4psi) the ignition system is powered, and sparks will start to be produced. If you are testing something else and still have the spark plugs in, you could get a start happen without intending to. :eek:

Remember, a door, once opened, may be passed through in both directions. ;)

Chris.....
 
Last edited:
You must log in or register to reply here.
Top