No Power to Fuel Pump

[skydyvyr]

I asked this question in another thread where it was suggested that I create a new thread for it, so here goes:

I have a 1994 Merc 4.3l in a no name 19.5' boat whose manufacturer is long out of business. I believe that the fuel pump is not receiving +12v after ignition. I assume that the problem is with the Oil Pressure switch, however, my particular installation appears to have two switches/senders on a brass t-fitting. My assumption is that one powers the fuel pump and the other sends a signal to the oil pressure gauge.

My question is threefold;
--Is this a stock setup or something that a previous owner did?
--If it is a stock setup, can anyone here assist me in determining which unit on the t-fitting is the switch for the Fuel Pump (I really don't want to pull the harness apart to find out)?
--If this is not a stock setup, is there a switch that will perform both functions so I can get rid of the brass t-fitting, and if so, can you provide a Merc Part number so that I can order the correct part?

Thanks for any assistance you can provide.

 

[Haut Medoc]

Re: No Power to Fuel Pump

I gotta head out, but the one with the purple wire should be the one.....
Try a temp jumper to see if it is the switch, & check the connections....​

 

[danfrompgh]

Re: No Power to Fuel Pump

The sender with 2 wires,one purple should be oil presure. My 2000 Bayliner with a 5.0 also has the brass T so yours is probably factory. Check the connector to the pump too for a bad connection, mine was bad and drove me nuts trying to find the intermitent pump failure..easy fix tho. GL!

 

[Don S]

Re: No Power to Fuel Pump

Yes, the tee'd switch and sender are normal on some models, and they look like this.

The oil pressure sender has both purple (power) and purple/yellow (pump and choke power) wires going to it. The gauge sender has a light blue wire.