Volvo Penta wiring change

[llewis01]

I have a 1994 volvo penta 454. I'm changing the alternator to higher amp. My old alternator is a presolite 5 wire and changing to a 3 wire alternator. My question is what the wiring diagram should be to do the change? I need the higher amp alternator to power all of my electronics.
Any help would be great.

 

[alldodge]

VP keeps the pump ON thru the ALT (Green wire thru diode). If motor dies the ALT stops and power thru the ALT to the fuel pump stops

You want to wire it up as a Merc and may want to add a oil pressure switch. Starter powers pump while cranking and and purple wire keeps it going when running

My thought is to remove the fuel pump relay and just use the oil pressure switch

Disconnect fuel pump relay
Disconnect Green wire from ALT to fuel pump relay thru diode, cap off
Disconnect Yellow/Red wire to fuel pump relay

The Yellow/Red to relay goes moves to fuel pump hot side and oil pressure switch normally open (NO) side of oil pressure switch

Purple ignition wire goes to other side of oil pressure switch and The excite side of the ALT. Also connect to electric choke on carb

Connect Red/Purple from start assist relay to Field side of ALT

 

[llewis01]

VP keeps the pump ON thru the ALT (Green wire thru diode). If motor dies the ALT stops and power thru the ALT to the fuel pump stops

You want to wire it up as a Merc and may want to add a oil pressure switch. Starter powers pump while cranking and and purple wire keeps it going when running

My thought is to remove the fuel pump relay and just use the oil pressure switch

Disconnect fuel pump relay
Disconnect Green wire from ALT to fuel pump relay thru diode, cap off
Disconnect Yellow/Red wire to fuel pump relay

The Yellow/Red to relay goes moves to fuel pump hot side and oil pressure switch normally open (NO) side of oil pressure switch

Purple ignition wire goes to other side of oil pressure switch and The excite side of the ALT. Also connect to electric choke on carb

Connect Red/Purple from start assist relay to Field side of ALT

I don’t have a yellow/red wire to the relay.

 

[alldodge]

Never said which model
Is your wiring similar to this one?

 

[llewis01]

Never said which model
Is your wiring similar to this one?

View attachment 341466

It is similar to mine. My is a Glimda model. Sorry about that.
Thanks

 

[alldodge]

By model I meant the motor model, is it a GL, GS etc?

The GL wiring above has a Yel/Red wire going to a diode to the fuel pump relay

Below is a Merc manual to electric fuel pump. The Yel/Red going to the inside small post on the starter, is used for one side of the switch. In your case it would run to the FP relay. The Green wire is removed and the Purple wire is feed to the same FP relay point

 

[llewis01]

It is similar to mine. My is a Glimda model. Sorry about that.
Thanks

This looks close to ours but we can’t tell where the yellow changes colors because it goes into a taped wire bundle.

 

[llewis01]

• Volvo Penta I/O & Inboard Gas Engines & Outdrives

Volvo Penta wiring change​

• Thread starterllewis01
• Start dateMay 6, 2021

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llewis01​

Seaman​

• May 6, 2021
• Add bookmark
• #1

I have a 1994 volvo penta 454. I'm changing the alternator to higher amp. My old alternator is a presolite 5 wire and changing to a 3 wire alternator. My question is what the wiring diagram should be to do the change? I need the higher amp alternator to power all of my electronics.
Any help would be great.

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[IMG alt="alldodge"]https://forums.iboats.com/data/avatars/m/144/144589.jpg?1602078948[/IMG]

alldodge​

Supreme Mariner​

• May 6, 2021
• Add bookmark
• #2

VP keeps the pump ON thru the ALT (Green wire thru diode). If motor dies the ALT stops and power thru the ALT to the fuel pump stops

You want to wire it up as a Merc and may want to add a oil pressure switch. Starter powers pump while cranking and and purple wire keeps it going when running

My thought is to remove the fuel pump relay and just use the oil pressure switch

Disconnect fuel pump relay
Disconnect Green wire from ALT to fuel pump relay thru diode, cap off
Disconnect Yellow/Red wire to fuel pump relay

The Yellow/Red to relay goes moves to fuel pump hot side and oil pressure switch normally open (NO) side of oil pressure switch

Purple ignition wire goes to other side of oil pressure switch and The excite side of the ALT. Also connect to electric choke on carb

Connect Red/Purple from start assist relay to Field side of ALT

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llewis01​

Seaman​

• Yesterday at 3:29 PM
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• #3

alldodge said:
VP keeps the pump ON thru the ALT (Green wire thru diode). If motor dies the ALT stops and power thru the ALT to the fuel pump stops

You want to wire it up as a Merc and may want to add a oil pressure switch. Starter powers pump while cranking and and purple wire keeps it going when running

My thought is to remove the fuel pump relay and just use the oil pressure switch

Disconnect fuel pump relay
Disconnect Green wire from ALT to fuel pump relay thru diode, cap off
Disconnect Yellow/Red wire to fuel pump relay

The Yellow/Red to relay goes moves to fuel pump hot side and oil pressure switch normally open (NO) side of oil pressure switch

Purple ignition wire goes to other side of oil pressure switch and The excite side of the ALT. Also connect to electric choke on carb

Connect Red/Purple from start assist relay to Field side of ALT
Click to expand...

I don’t have a yellow/red wire to the relay.

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[IMG alt="alldodge"]https://forums.iboats.com/data/avatars/m/144/144589.jpg?1602078948[/IMG]

alldodge​

Supreme Mariner​

• Yesterday at 5:05 PM
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• #4

Never said which model
Is your wiring similar to this one?

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llewis01​

Seaman​

• Today at 9:10 AM
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• #5

alldodge said:
Never said which model
Is your wiring similar to this one?

View attachment 341466

It is similar to mine. My is a Glimda model. Sorry about that.
Thanks

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[IMG alt="alldodge"]https://forums.iboats.com/data/avatars/m/144/144589.jpg?1602078948[/IMG]

alldodge​

Supreme Mariner​

• Today at 9:31 AM
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• #6

By model I meant the motor model, is it a GL, GS etc?

The GL wiring above has a Yel/Red wire going to a diode to the fuel pump relay

Below is a Merc manual to electric fuel pump. The Yel/Red going to the inside small post on the starter, is used for one side of the switch. In your case it would run to the FP relay. The Green wire is removed and the Purple wire is feed to the same FP relay point

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llewis01​

Seaman​

• Today at 9:59 AM
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• #7

llewis01 said:
It is similar to mine. My is a Glimda model. Sorry about that.
Thanks

This looks close to ours but we can’t tell where the yellow changes colors because it goes into a taped wire bundle.

 

[llewis01]

Got it wired up with using a Holley pressure switch. When you turn on the key, the fuel pump runs. I don’t think it should do that.

 

[alldodge]

Got it wired up with using a Holley pressure switch. When you turn on the key, the fuel pump runs. I don’t think it should do that.

Correct, you don't
The common should go to the pump
The wire that is hot when key is on, should go to the Normally Open (NO) side (the Purple wire)
The side that goes hot when cranking, should go to the Normally Closed (NC).

If the fuel pump is on the correct place on the switch, then swap the other leads, but again it should be on the Common connection (also called switched leg)