Wiring harness for 1993 Mercruiser v6 with balanced shaft and electric fuel pump

dlogvine

Master Chief Petty Officer
Joined
May 4, 2015
Messages
832
I'm trying to reuse the existing wire harness for the newly rebuild 1993 Mercruiser 4.3 with the balance shaft and electric fuel pump. What I have available is an older 1984 Mercruiser 4.3 without a balanced shaft harness and a 1993 mercruiser v8 5.0l harness. Neither of the older engines had an electric fuel pump and there are possibly some other electrical differences. Still I wonder if I can use any of these harnesses and which one would be a better match. Thx
 

wrench 3

Commander
Joined
Aug 12, 2012
Messages
2,108
As near as I can make out the '93 5.0l is almost identical to the 4.3l. It's just missing the fuel pump circuits. It just needs a ground, an ignition supply running through an oil pressure switch and a wire running from the unused small terminal on the starter solenoid to the pump side of the oil pressure switch.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Yep, as AD said... Use the '93 and just run a few new wires for the pump...

Chris.....
 

Rick Stephens

Admiral
Joined
Aug 13, 2013
Messages
6,118
I used the older harness and built the engine side while the motor was on a stand. Adding the electric fuel pump circuitry is easy that way. Don't forget a fuse. I also added a relay switched by both oil pressure switch and starter. The relay protects the oil pressure switch from directly powering a pump all the time.
 

wrench 3

Commander
Joined
Aug 12, 2012
Messages
2,108
If you're adding a fuse and a relay that will be in the engine compartment don't forget to make sure that they're vapor proof (ignition protected).
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
If you're adding a fuse and a relay that will be in the engine compartment don't forget to make sure that they're vapor proof (ignition protected).

If you find a closed 20 amp mini blade fuse (ATC), please let me know where. Can't get them in Australia. :mad:
 

wrench 3

Commander
Joined
Aug 12, 2012
Messages
2,108
I use these
fetch
https://www.iboats.com/shop/sierra-fuse-holder-inline-weatherprf.html
They take ATO or ATC fuses and are rated for 30amps.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
I use these https://www.iboats.com/shop/sierra-fuse-holder-inline-weatherprf.html
They take ATO or ATC fuses and are rated for 30amps.

Yeah, that's the holder. I'm looking for the (mini) fuses themselves. Plenty of sites on flea-bay and the like CLAIMING to sell ATC, but when you quiz them, no, only ATO... I only run one value fuse on the engine (which is what I want the spares for) and that 20A. A 'mixed' pack is no good to me, since I only want 20A fuses. I know they are made, but re-sellers in Australia only carry ATO. Or 'marine dealers' who want over $10 each. That's just ridiculous!

Chris.....
 

wrench 3

Commander
Joined
Aug 12, 2012
Messages
2,108
Bluesea lists one as ATO/ATC. I have an inquiry in to them now. I'll let you know if the reply is positive but I'm not too hopeful.
 

wrench 3

Commander
Joined
Aug 12, 2012
Messages
2,108
Chris
I was going to send you a personal message but since we've already hijacked the thread.:D
I received this information from Bluesea:
"Mike,
Thank you for the question. This is a common misconception about automotive fuses. ATO is the brand name used by Little Fuse. ATC is the brand name used by Cooper Bussmann. We may use either brand depending on availability. The O or C has nothing to do with the construction of the fuse only the Brand the fuse was manufactured under. Both brands have almost identical characteristics but we want consumers to know you could receive either brand. Currently our stock is the Cooper Bussmann ATC’s."
I sent back asking if they were ignition protected and got this back:
"Mike,
Both brands are ignition protected. Here is the Bussmann page

You can get them here. (iBoats)
Blue Sea Systems ATO or ATC Marine Fuse, 20A, (2)IB00242475$2.19$1.86
 

Attachments

  • photo306810.jpg
    photo306810.jpg
    77.2 KB · Views: 0

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Chris
I was going to send you a personal message but since we've already hijacked the thread.:D
I received this information from Bluesea:
"Mike,
Thank you for the question. This is a common misconception about automotive fuses. ATO is the brand name used by Little Fuse. ATC is the brand name used by Cooper Bussmann. We may use either brand depending on availability. The O or C has nothing to do with the construction of the fuse only the Brand the fuse was manufactured under. Both brands have almost identical characteristics but we want consumers to know you could receive either brand. Currently our stock is the Cooper Bussmann ATC’s."
I sent back asking if they were ignition protected and got this back:
"Mike,
Both brands are ignition protected. Here is the Bussmann page

You can get them here. (iBoats)
Blue Sea Systems ATO or ATC Marine Fuse, 20A, (2)IB00242475$2.19$1.86

Fantastic, thank you...

Edit: Just checked, those fuses look like 'regular' fuses, not 'mini'... Also, I checked and it seems your man is spinning you some...

fuses.JPG
 
Last edited:

Mad Props

Lieutenant Commander
Joined
Jul 8, 2016
Messages
1,766
achris I dunno if it's what your looking for but I though the minis were called ATM fuses. I get tons of availability on amazon, etc, when I search 20 amp atm fuses. Bussmann shows them as J1171 approved.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
achris I dunno if it's what your looking for but I though the minis were called ATM fuses. I get tons of availability on amazon, etc, when I search 20 amp atm fuses. Bussmann shows them as J1171 approved.

Thanks, I'll check it out... Here's the sizes of the fuses...

fuses.JPG
 

dlogvine

Master Chief Petty Officer
Joined
May 4, 2015
Messages
832
Wow, did not expect my question to open such a discussion. Appreciate all the input. As for the ATC and ATO fuses, I always thought ATO corresponds to the Open fuse element, while ATC ment Closed element. Most of the automotive modern fuses are ATC. The mini fuses areATM.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Wow, did not expect my question to open such a discussion. Appreciate all the input. As for the ATC and ATO fuses, I always thought ATO corresponds to the Open fuse element, while ATC ment Closed element. Most of the automotive modern fuses are ATC. The mini fuses areATM.

Yes, but the minis also come in open and closed... THAT is the problem I'm having.

Cheers.
 

wrench 3

Commander
Joined
Aug 12, 2012
Messages
2,108
I always thought that the ATOs were an open case and ATCs were a closed case but when the guy came back to me with that, I figured I'd been wrong all these years.
Sorry if I gave you false hope. When you mentioned ATC fuses I assumed you wanted the mid size.

Hope you can find a supplier for the Bussman ATMs.
Mike
 

dlogvine

Master Chief Petty Officer
Joined
May 4, 2015
Messages
832
I saw a bunch if offerings for the ATC fuse boxes and enclosures on Ebay and Amazon. And they are pretty cheap, and sold in bucks, like 5 for $10.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
I saw a bunch if offerings for the ATC fuse boxes and enclosures on Ebay and Amazon. And they are pretty cheap, and sold in bucks, like 5 for $10.

Don't want the boxes, just the fuses to go in them, and I don't want a mixed bag of 100 fuses, just 20A...

Thanks anyway.

Chris.....
 
Top