why do I have 2 fuel pumps??

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airjohn81
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why do I have 2 fuel pumps??

Post by airjohn81 » Thu Jan 22, 2015 5:50 pm

Had a fuel pump crap out and noticed I have 2 aeromotive 9psi pumps.. its a 454 gm crate w 750crm dbl pump mec secondaries. .. bought boat used a while back an never noticed the 2 pumps.. both are obviously bad but cant imagine they went at the same time.. used a small 7psi pump and wont hold enough pressure at wot to hold rpms.. can I run a single holley pump w regulator or do I need 2 pumps.. first glance I thought I was just a back up pump.. never seen 2 on a car.. Im lost .. thanks in advance
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Re: why do I have 2 fuel pumps??

Post by 21DiamondB » Thu Jan 22, 2015 5:54 pm

No reason for two fuel pumps on your setup. Generally the aeromotives are much better than the Holleys. If you're looking to save money you could also go with the Carter fuel pump from Napa that half of the airboat companies install from the factory.
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Re: why do I have 2 fuel pumps??

Post by Longdraw » Thu Jan 22, 2015 5:57 pm

x2 carter will work fine, may have had 2 if one failed

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Re: why do I have 2 fuel pumps??

Post by airjohn81 » Thu Jan 22, 2015 5:58 pm

What psi an gph should I be looking for ...thank you..
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Re: why do I have 2 fuel pumps??

Post by 21DiamondB » Thu Jan 22, 2015 6:04 pm

With the Carter there is no need for a fuel pressure regulator.
-------- 16.5 x 8 Diamondback - 632ci - Oxbox 2. 55 - Sensenich 5-Blade JX---------

barhopper
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Re: why do I have 2 fuel pumps??

Post by barhopper » Thu Jan 22, 2015 6:07 pm

I have two on mine. Only one is in use. The other one is a backup in case the first fails.

SWAMPHUNTER45
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Re: why do I have 2 fuel pumps??

Post by SWAMPHUNTER45 » Thu Jan 22, 2015 6:45 pm

I run a Carter Marine and it works well, but the Mallory COMP110 self regulated or COMP140 external regulated are stronger and better pumps.

Check out the COMP110 if you need gas in volume

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Re: why do I have 2 fuel pumps??

Post by rjonesboy » Thu Jan 22, 2015 8:21 pm

I have had several carter or carter style (NAPA) fuel pumps over the last 25 years. Never had one quit pumping, but had a few that the internal regulator go bad and would flood out the carb

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Re: why do I have 2 fuel pumps??

Post by happy harold » Fri Jan 23, 2015 8:21 am

X2

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Deano
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Re: why do I have 2 fuel pumps??

Post by Deano » Fri Jan 23, 2015 8:58 am

airjohn81 wrote:What psi an gph should I be looking for ...
Be aware that Holley carbs are designed to operate with 7 psi. Having much beyond that can create other problems.
Not to imply that this is the case in your instance, but it seems the majority of the time, such problems when using carbs similar to yours, is a decided lack of volume . . . not with the pressure. Lots of times, installing larger ID fuel lines will solve the problem if the pump is healthy enough to still maintain 7 psi. with the bigger fuel line. Of course, that would be contingent on there not being other restrictions between the tank pickup and the float bowl.

Again, I don't mean to imply that the pump is not the problem (although it may not be), but if it were me, I would also be looking for any flow restrictions in the delivery system. Small fuel lines would be easiest to identify, fuel filter(s) needing serviced, the pickup in the tank, and internally decomposing (from ethanol) rubber fuel lines, could all be contributing factors to such a condition. Have you checked the filter in the carb inlet?

If there are two pumps installed, that would imply to me that there may very well have been such a restriction that hadn't been successfully identified and dealt with.
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airjohn81
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Re: why do I have 2 fuel pumps??

Post by airjohn81 » Fri Jan 23, 2015 9:38 am

Deano wrote:
airjohn81 wrote:What psi an gph should I be looking for ...
Be aware that Holley carbs are designed to operate with 7 psi. Having much beyond that can create other problems.
Not to imply that this is the case in your instance, but it seems the majority of the time, such problems when using carbs similar to yours, is a decided lack of volume . . . not with the pressure. Lots of times, installing larger ID fuel lines will solve the problem if the pump is healthy enough to still maintain 7 psi. with the bigger fuel line. Of course, that would be contingent on there not being other restrictions between the tank pickup and the float bowl.

Again, I don't mean to imply that the pump is not the problem (although it may not be), but if it were me, I would also be looking for any flow restrictions in the delivery system. Small fuel lines would be easiest to identify, fuel filter(s) needing serviced, the pickup in the tank, and internally decomposing (from ethanol) rubber fuel lines, could all be contributing factors to such a condition. Have you checked the filter in the carb inlet?

If there are two pumps installed, that would imply to me that there may very well have been such a restriction that hadn't been successfully identified and dealt with.
I did check the inlet filters, lines, filter from tank, and pickup plus blew thew all out regardless to be sure.. the pump i installed just to make sure it was a pump problem is way to small of a pump an pretty much knew it but was using it to make sure i wasnt crazy... the wierd thing about the 2 pumps is that they both are wired together.. so as if to use 1 for back up i should put 1 on a emergency type switch instead of both running at the same time... i would think that could burn up the pumps quicker.. like 1 scavenging from the other.. idk.. i found another aeromotive pump last night an installing today it is 7psi internally regulated.. i am going to order the carter pump and install the an use the other for back up just not runnig both at the same time.. what ya think?? thanks dave
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Re: why do I have 2 fuel pumps??

Post by Moritz » Sat Jan 31, 2015 10:49 pm

When I first got my boat new , I bought an extra fuel pump as a spare. The first carter pump one failed by high pressure with 2 hr on boat. The second after 10 min. Ran holly for 6 months and it froze up. Water on the seal. Replaced with cater 7 years still running.

Make sure you have a check valve between pump and tank so fuel does not drain back in to tank causing fuel pump to run dry- bad for the pump. I used a bulb that is used on out boards to prime the motor.

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Re: why do I have 2 fuel pumps??

Post by aggiejim » Tue Feb 03, 2015 11:34 pm

wht in the hell did i not think of that pump bulb good call that doesnt restrict flow though
16 x 8 floral city ls2 6.0 aluminun block 2.3 ch3
can u say addicted
16.5 x8 alumintech new build
6.0 ls2 2.3 ch3 3 blade
the aggie

aggiejim
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Re: why do I have 2 fuel pumps??

Post by aggiejim » Tue Feb 03, 2015 11:35 pm

why in the hell did i not think of that pump bulb good call that doesnt restrict flow though
16 x 8 floral city ls2 6.0 aluminun block 2.3 ch3
can u say addicted
16.5 x8 alumintech new build
6.0 ls2 2.3 ch3 3 blade
the aggie

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