Fuel Pump Switch / Oil Pressure Sender issue with Fuel Pump

[DangerMouse1]

Hi,
I am having issues at start. Engine will turn on for 30 seconds then die. I followed the advice on the forum and I bypassed the fuel pump switch and it will run fine. I can hear the fuel pump start when ignition is turned on when I bypass the fuel pump switch, as it used to.

I thought then the issue was at the fuel pump switch, so I decided to replace the whole component (fuel pump switch, oil pressure sender and 3 way brass fitting). I hooked it up, but I don't hear the fuel pump turning on, and have the same issue of engine only running for 30seconds, which I am assuming is just running from the carb bowl.

My understanding is the oil pressure sender is not involved with the starter circuit? I am not sure why the fuel pressure switch is not closed at start? Wondering if someone could point me in the right direction?

Engine is a 5.0 Carb Mercruiser - Serial - 0w332827

Thanks.

 

[alldodge]

Thanks for the SN

The carb bowl will fill completely in a few seconds. Once filled, it will run for several minutes before bowl runs dry. The 30 seconds is a hard to figure issue.

If fuel pump does not turn ON during cranking, then need to check the wiring.

When cranking power comes from the starter to the fuel pump. If the fuse blew it would not. Once running, oil pressure builds and power goes thru switch to power it