help converting from mechanical to electric fuel pump

[xlav8r]

I have a 91 4.3 mercruiser that I changed blocks on. My new block needs to have an electric fuel pump installed. What would be the proper way to install a marine electric fuel pump. ie. check valve which side of pump?, fuel filter or seperator , which side of pump?, what particular oil switch is needed?, can I run flexable fuel lines to carb?, what modifications need to be added to wiring? Is there a fuel pump holder available or must I make one. Where should I mount new pump?

thanks

Brent

 

[firecapt13]

Re: help converting from mechanical to electric fuel pump

I got my pump and switch from Advanced auto parts it is Airtex #8337 and they have the switch also. I had to do the same thing on a 92 4.3 the pump and switch was under 100 and had the bracket with it. I ran all fuel lines in 3/8 and rubber all the way to carb

 

[achris]

Re: help converting from mechanical to electric fuel pump

Brent,

Download one of the later service manuals for a V6 and all the diagrams are in there. Just remember to put an oil pressure switch and a starter solenoid bypass in the circuit.

Chris..........

 

[hcooperrn]

Re: help converting from mechanical to electric fuel pump

I've been lurking for a long time, but I think I can help you out a little. I just got by boat running after the same thing -- replaced the 4.3l Mercruiser with a newer non-mechanical block.

I've played with racing cars and motorcycles for awhile, so I went with Summit Racing. They have a marine approved universal Carter fuel pump, part#CRT-P4389, and I used part #SUM-G1438 as an oil pressure cut off switch. I'm planning on adding a proper fuse panel in the near future, so I went ahead and ran an ignition hot wire from the dash back to the pressure switch, a fused wire from the switch to the pump, and a ground wire to the block -- check out the Summit websitve and the oil pressure switch and you can see a detailed wiring diagram...

I also ran an ignition hot wire through a momentary push-button switch on the dash to the output side of the oil-pressure switch. This allows me to prime the pump and fill the fuel bowl with just a couple second push -- the engine fires right up, rather than cranking for a few seconds to prime.

For the pump itself, I had a bracket laying around from an OMC water separator filter that I bolted to the block, and the 3/8" fuel line goes from the tank to the filter, filter to fuel pump, and then up to the carb. The pump was able to pull enough vacuum to prime the entire setup in less than 5 seconds, and it flows 72gph at 6psi, perfect for a carb in good condition.

Hope that helps!

Forgot to mention, that fuel pump includes a mounting bracket, I just secured it into a safe place that I knew I would drill through the hull...

 

[hcooperrn]

Re: help converting from mechanical to electric fuel pump

Ha, I just read my own post again and saw that I said I drilled through the hull. Oops. I'm new to owning a boat, but thankfully, not that dumb.... My fuel pump is secured to a stringer.

 

[Bt Doctur]

Re: help converting from mechanical to electric fuel pump

Dont worry, already been done. Took a call to see where water was getting into a boat.
Came to find 36 3 inch long SS screws coming out the bottom of the hull from the new flooring that was just installed