electric fuel pump for 1993 Mercruiser 4.3 v6

[dlogvine]

Rebuilding chevy 1993 4.3 v6 engine w/balanced shaft for marine applications. Used older 1986 Mercruiser 4.3 v6 for accessories and spare parts. Older engine had a mechanical fuel pump, newer block does not have a hole for it, I think it was the year when Chevy started engines with balanced shafts and electric fuel pumps. There are plenty of aftermarket electric fuel pumps on ebay. Some say that they are good for marine applications but do not have SAE J1171 marine standard certification. Can I still use it or should I go with a used electric pump? Also where is the best place to find a mounting bracket for this fuel pump? Or can I use just a clamp of appropriate size? Thank you

 

[alldodge]

Use only marine electric fuel pump. Need no more then 7 psi, or can use a higher one with a inline regulator

Carter
Holley
Airtex
Others

 

[Rick Stephens]

When I built my motor I had a non-balance shaft but with no mechanical pump block. I used the OEM Airtex, which is the E11003. Currently prices around $65. Then I could use the Mercruiser factory mounting hardware and plumbing wherever needed.

 

[stonyloam]

Are you adding a oil pressure switch and fuel pump relay? A safety requirement with an electric pump in a boat.

 

[dlogvine]

I installed the oil pressure switch, however, im not sure where does the fuel pump relay goes, I look at the wiring diagram for this engine, does not have a fuel pump relay.

 

[alldodge]

A relay doesn't have to be used, but can help protect the loads. To install without relay

 

[Rick Stephens]

If you add a relay you take the load of the pump off the oil pressure switch. Wires in like this.

 

[stonyloam]

Nice explanation and diagram Rick. The relay should be more reliable over the long run.

 

[achris]

The current pulled by the pump is way less than the switch is rated for, so the relay, as nice and 'more professional' as it is, isn't actually essential. And for the record, if I was setting one up now, I'd do it with a relay (and fuse)... Just make sure it's a mini blade fuse and water proof holder, not a 3AG glass fuse.... And make sure you get an 'ignition protected' relay, not a solenoid... (relay is designed for continuous use, a solenoid is more a 'momentary' or very low duty cycle device, and generally not designed for continuous operation. Yes you can get 'continuously rated' solenoids, but they are usually expensive, and designed for HIGH currents, not the few amps you'll be drawing.)....

Chris........

The fuse and holder...



'Ignition protected' relay....

 

[Rick Stephens]

Thanks Chris. Not sure why I called it a solenoid... similar, but as noted not the same. I did use a relay, not a solenoid. There are some really nice sealed ones out these days.

 

[Lou C]

Also put an ATC fuse in that holder (closed style so meets J1711) not the open ATO style....

 

[achris]

Also put an ATC fuse in that holder (closed style so meets J1711) not the open ATO style....

J1711: "Recommended Practice for measuring the exhaust emissions and fuel economy of hybrid-electric vehicles, including plug-in hybrid vehicles"

How does a closed fuse helps meet that :noidea:

Maybe you mean SAE-J1171? :lol::lol::lol::lol::lol:

Sorry, couldn't resist,

Chris.......

 

[Lou C]

Lol right!
a little known fact is that those ATO fuses are open in the area between the blades and therefore are not ignition protected. ATC is...got this info off of Eaton’s website...

 

[Lou C]

http://www.cooperindustries.com/cont...s-2009-atc.pdf

last page table 2

I called Blue Seas tech service about their water proof fuse holders. The tech guy told me that these fuse holders are not rated as ignition protected because people might put the wrong fuse in them (ATO) instead of the right one (ATC). Basically what I got from them was that if you want to use those fuse holders, if you use ATC fuses you are meeting the letter of the law and it is safe to do so. Of course they could have labeled them as "use ATC fuses only to meet SAE J1171" but for some reason they did not. I have 3 of these Blue Seas water proof fuse holders in my engine compartment so this was good to find out....

 

[achris]

:facepalm: are you seriously telling me an open fuse in a WATERPROOF holder is an ignition source? If water molecules can't get in, then petrol molecules DEFINITELY can't get in.

Open fuse in open holder, yeah sure, it's a problem. Open fuse in closed holder, no problem.

That Blue Sea tech is an idiot!

Chris....

 

[Lou C]

Chris you are forgetting one important fact:
this is the USA where anybody can sue anybody for anything. So if you have electrical equipment in an engine compartment that is not ignition protected then you better mitigate the risk anyway you can. An with that document I posted it proves you were at least reasonably prudent in the event of an unfortunate accident.

 

[achris]

...this is the USA where anybody can sue anybody for anything. ...

Good point...

 

[dlogvine]

I got the fuse part. Will definitely put one in the circuit, however, I'm not clear as to why I should use relay in this low power fuel pump. To me it seems like a redundant part. I could be wrong, but would like to know why it is needed. Thx