1987 4.3 mercruiser fuel pump ???

[Clarko1988]

So I bought a 1987 marlin 4.3 are these suppose to have fuel pumps? Cause this motor does not have a mechanical fuel pump. It has a big fuel pump the reason I'm asking is because I rebuilt carb and it is over filling. Checked the float needle and seat and it is all clear I am stumped and getting really annoyed. Lol

 

[Fun Times]

Does your fuel pump look like this one at all? https://www.mercruiserparts.com/bam/subassembly/31472/919/80

 

[Clarko1988]

No the one that is on the motor is electric

 

[Clarko1988]

Also the needle seat suppose to be a little dowel or a springin the carburetor float bowl?

 

[Rick Stephens]

You will need to post serial number on your motor for an answer to parts details.

Originally, an '87 would have had a mechanical pump. If you want some info on your setup, post some pics.. Also, make certain there is an oil pressure switch to run that pump. This is what keeps your boat from becoming a bomb and is absolutely necessary for safe operation.

 

[achris]

So I bought a 1987 marlin 4.3 are these suppose to have fuel pumps? Cause this motor does not have a mechanical fuel pump. It has a big fuel pump the reason I'm asking is because I rebuilt carb and it is over filling. Checked the float needle and seat and it is all clear I am stumped and getting really annoyed. Lol

You bought a boat without a test drive?

 

[Clarko1988]

You will need to post serial number on your motor for an answer to parts details.















































































































































































































































































































































































































































































































































































































































































































































































































































































































































Originally, an '87 would have had a mechanical pump. If you want some info on you







r setup, post some pics.. Also, make certain there is an oil pressure switch to run that pump. This is what keeps your boat from becoming a bomb and is absolutely necessary for safe operation.

You will need to post serial number on your motor for an answer to parts details.

Originally, an '87 would have had a mechanical pump. If you want some info on your setup, post some pics.. Also, make certain there is an oil pressure switch to run that pump. This is what keeps your boat from becoming a bomb and is absolutely necessary for safe operation.

So how do I wire up the fuel pump correctly? There is one wire on my oil pressure switch

 

[achris]

That's an oil pressure sender (for the gauge), not a switch. You need to add a tee and a (NC) switch.

 

[Rick Stephens]

Looks like this:

 

[Clarko1988]

So confused lol

 

[Rick Stephens]

Basic wiring in english:

Power to the pump comes from two places -

1)the ignition switch via purple wire to and through the oil pressure switch
2)the outside small lug on the starter solenoid that acts as a primer when the motor is cranking through the purple/yellow wire.

Purpose of this is that if the engine dies and the key is on, if by any chance there is dirt in the carburetor needle valve or a leak anywhere, you don't fill the bilge with gasoline. Fuel vapors in the bilge have nowhere to go - one little spark and boom.

 

[Clarko1988]

Do you have pictures on how to wire to the pressure switch? That would be under the dash correct?

 

[achris]

... That would be under the dash correct?

No, the pressure switch is installed on a tee with the oil pressure sender on the left hand side of the engine block.

Wiring of the switch is easy. One side has power from the ignition, the other goes to the fuel pump.

Chris......

 

[Rick Stephens]

No, the pressure switch is installed on a tee with the oil pressure sender on the left hand side of the engine block.

Wiring of the switch is easy. One side has power from the ignition, the other goes to the fuel pump.

Chris......

On mine the oil pressure switch is at the back of the motor to the port side of the distributor. Either way, the pressure switch is just a pass through, when there is pressure, the power is connected to the pump.

 

[achris]

On mine the oil pressure switch is at the back of the motor to the port side of the distributor. Either way, the pressure switch is just a pass through, when there is pressure, the power is connected to the pump.

I know the passage you're referring to. On later engines, that port is plugged, and tee is used with the sender.

Chris.......

Here's what the OP needs...

 

[Rick Stephens]

I know the passage you're referring to. On later engines, that port is plugged, and tee is used with the sender.

Chris.......

Here's what the OP needs...
View attachment 355131

Yah. My block is pre-balance shaft. Oldish, like me.

 

[Clarko1988]

I've got the pressure switch. So do I attach wire from the switch to the stater solenoid? Or the starter it's self?

 

[achris]

There should be an unused post on the starter, use that. (See Rick's diagram)

 

[Clarko1988]

There should be an unused post on the starter, use that. (See Rick's diagram)

thank you so much.