Merc. 5.7 Repower wiring

[mrjamieson]

Hi guys, I have a 1992 Wellcraft 233 Eclipse which had a T/B IV ignition, mechanical fuel pump and Rochester 4bbl. Got new outdrive, transom assembly and MarinePower 5.7 with, Delco EST, electric fuel pump and Holley 1409 4bbl. First, the fuel pump wiring. The oil pressure switch has a "P", "S" and an "I" on it. Should I put an inline fuse before the (+) fuel pump from the "P" side? If so, how many amps? Does the "S" go to the "S" (right post) on the starter OR the "R" (left post) on the starter? Can I splice into the purple (+) wire coil wire for the "I" side? Also, can I use this switch for the "low pressure alarm too"? If so, how do I wire it? I would hate to have (2) oil pressure switches and one oil pressure sender. Secondly, the Holley carb. Using the SELCO repair manual, (the picture is not that clear) I see the electric choke being fed from the "R" (left post) side of the starter (I think), is that correct? The Holley website made it clear you can NOT use the coil or alternator as a power source. Thirdly, the shift interrupt wiring. The new wiring seems to "energize" the distributor as apposed to the old way of "grounding" it. If that's correct, can I splice into the same purple wire as the oil pressure switch? Should I use a 2 amp inline fuse before the shift interrupter as some illustrations suggest? Lastly, Should I use 12 or 14 gauge wire. Thanks in advance.

 

[Rick Stephens]

I did not put a fuse on the interrupter circuit.

10 amp circuit breaker plenty for the pump. I stuck a relay to power the pump. I just connected the wires together coming from oil pressure switch and starter wire (purp/yellow) to switch the relay. Then I put a 10 amp circuit breaker on the power side of the relay. This setup is easiest on the oil pressure switch.

The purple wire coming off the ignition switch runs to choke, EST and fuel pump switch. 14 Gauge is perfect.

Toss the Seloc in the trash and get a OEM Mercruiser Service Manual. You will thank yourself for that.

 

[mrjamieson]

I did not put a fuse on the interrupter circuit.

10 amp circuit breaker plenty for the pump. I stuck a relay to power the pump. I just connected the wires together coming from oil pressure switch and starter wire (purp/yellow) to switch the relay. Then I put a 10 amp circuit breaker on the power side of the relay. This setup is easiest on the oil pressure switch.

The purple wire coming off the ignition switch runs to choke, EST and fuel pump switch. 14 Gauge is perfect.

Toss the Seloc in the trash and get a OEM Mercruiser Service Manual. You will thank yourself for that.



View attachment 353674

Thanks for the reply. Edelbrock (I don't know why I kept saying Holley) said not to use the purple from either the alternator or the coil. Will the pur/yel from the starter work for the electric choke? Also, that picture has a two wire OPS, mine is a 3 wire. Should I use the OEM 2 wire switch? If so, do you have a part #? Thanks

 

[Scott06]

Thanks for the reply. Edelbrock (I don't know why I kept saying Holley) said not to use the purple from either the alternator or the coil. Will the pur/yel from the starter work for the electric choke? Also, that picture has a two wire OPS, mine is a 3 wire. Should I use the OEM 2 wire switch? If so, do you have a part #? Thanks

Mercruiser runs the electric choke off the purple wire going to ignition on.
they say to do this so as not to lower voltage off the ignition circuit. On my old GTO i ran the electric choke off the wiper circuit upstream of the wiper switch. Easier in a car where the fuse box is. 4 ft from the choke vs a boat.
you can see the factory wiring that rick gave above to the choke. If you follow this you will be fine, either purple or purple yellow is fine.

 

[Rick Stephens]

Pur/Yel from the starter is only hot when the starter is cranking.

 

[Scott06]

Pur/Yel from the starter is only hot when the starter is cranking.

My merc takes the purple to the choke, but In the drawing you posted the purple yellow is fed via the oil pressure switch as well As getting power off starter when cranking

 

[Scott Danforth]

ABYC standard wire colors

purple is ignition
purple with yellow stripe is ignition while cranking
yellow with red stripe is crank signal

the purple wire from the round plug goes to the coil + and to the choke. It also goes to the relay that powers the fuel pump that is piloted off the oil pressure switch.

no reason to put a fuse in the shift interrupt circuit.

 

[mrjamieson]

Mercruiser runs the electric choke off the purple wire going to ignition on.
they say to do this so as not to lower voltage off the ignition circuit. On my old GTO i ran the electric choke off the wiper circuit upstream of the wiper switch. Easier in a car where the fuse box is. 4 ft from the choke vs a boat.
you can see the factory wiring that rick gave above to the choke. If you follow this you will be fine, either purple or purple yellow is fine.

I see those schematic's where the purple wire is powering the electric choke, but, those are 2 BBL carbs. only. The 4 BBL carbs. (again according the the Edelbrock tech line) should NOT be powered by the purple wire from the coil or alternator. Still confused. Thanks

 

[Scott Danforth]

I see those schematic's where the purple wire is powering the electric choke, but, those are 2 BBL carbs. only. The 4 BBL carbs. (again according the the Edelbrock tech line) should NOT be powered by the purple wire from the coil or alternator. Still confused. Thanks

tech is wrong. choke coil is same regardless of 1-barrel, 2-barrel or 4-barrel.

 

[Scott06]

I see those schematic's where the purple wire is powering the electric choke, but, those are 2 BBL carbs. only. The 4 BBL carbs. (again according the the Edelbrock tech line) should NOT be powered by the purple wire from the coil or alternator. Still confused. Thanks

No difference on choke coil between a 2 or 4 bbl carb. I put a edelbrock 1409 on my previously 2 bbl carbed 5.0 merc, used the factory purple wire it works fine

 

[mrjamieson]

No difference on choke coil between a 2 or 4 bbl carb. I put a edelbrock 1409 on my previously 2 bbl carbed 5.0 merc, used the factory purple wire it works fine

ok, thanks

 

[mrjamieson]

Pur/Yel from the starter is only hot when the starter is cranking.

I got the relay but it's a 5 wire unit. Can you cut the middle wire. Would you mind sending a detailed pic of how to wire it? Also, is it OK to solder a 12 and 14 gauge wire together? All the relays and in-line fuses seem to be 12 gauge. Thanks

 

[nola mike]

I got the relay but it's a 5 wire unit. Can you cut the middle wire. Would you mind sending a detailed pic of how to wire it? Also, is it OK to solder a 12 and 14 gauge wire together? All the relays and in-line fuses seem to be 12 gauge. Thanks

Not sure what relay you got or what wire you're talking about. Standard 5 terminal relay you just don't use the 87a terminal. You can solder the wires together, just limit current to whatever the smallest wire can handle. For the relay, terminals 87 and 30 are connected when energized, so one of these terminals is your 12v power, and the other is going to the fuel pump. 86 and 85 are the trigger circuit, with one going to ground and the other coming from the p terminal of the oil pressure switch. I terminal gets a switched ignition wire, and S terminal gets 12v only when cranking, either from starter or starter slave solenoid.

 

[mrjamieson]

Not sure what relay you got or what wire you're talking about. Standard 5 terminal relay you just don't use the 87a terminal. You can solder the wires together, just limit current to whatever the smallest wire can handle. For the relay, terminals 87 and 30 are connected when energized, so one of these terminals is your 12v power, and the other is going to the fuel pump. 86 and 85 are the trigger circuit, with one going to ground and the other coming from the p terminal of the oil pressure switch. I terminal gets a switched ignition wire, and S terminal gets 12v only when cranking, either from starter or starter slave solenoid.

Great, thanks