Fuel pump wont shut off

recently I had to replace the starter on my mercruiser 4.3 and while I was doing so the fuel pump turned on and will not shut off even if you take the key out of the ignition. I'm also having the same problem with the engine. Turns on just fine but will not shut off with the key. I did some research and thought the problem was the diode but I replaced it and that did nothing.

Did you happen to replace the alt? Fuel pump has a pressure switch and cannot run without oil pressure

Sounds like you need to clock the fuel pump power wire on the starter solenoid away from the power post on the solenoid.

Ayuh,..... Sounds like ya wired the starter wrong,......

Telmor, I think that you should take another look at what may be wrong.


The starter motor's solenoid should offer either 3 or 4 posts (depending on the style).

..... one large post that powers the armature's field (not intended for the user to add anything to it)
..... one large post for the Common cable connection (main cable from battery switch).
..... one small S terminal for the yellow/red stripe wire that comes from the key switch S terminal.
..... and possibly one that will be labeled either R or I that would be part of the start-by-pass circuit.






The only two wires that could be inadvertently swapped (due to the ring eyelet size) would be at the S terminal and at the R or I terminal.

The S terminal requires power from the key switch in order to energize the solenoid's field, which in turn closes the main solenoid contacts.
The R or I terminal is an output terminal that is only energized when the main contacts are close.

If the R or I terminal wire was inadvertently connected to the S terminal, the ignition circuit would likely energize the solenoid's magnetic field, which in turn would operate the starter motor. In this scenario, the starter motor would continue to operate while the engine is running.

If the S terminal wire was inadvertently connected to the R or I terminal, you would get zero results when the key switch was in the start position.


There are several ways to energize the electric fuel pump during cranking when the N/O low oil pressure switch is open.
1..... the use of the R or I terminal (no feed back).
2..... the S terminal triggering a relay (relay preventing feed back).






.