Fuel system question?
+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 14 of 17

Thread:
Fuel system question?

  1. #1
    sox
    sox is offline
    Junior Member
    Join Date
    Jul 2012
    Posts
    2

    Default Fuel system question?

    Just installed a holley electric fuel pump in my 73' tahiti jet. I mounted it to the transom just above the jet bowl. Its being fed by 2 side tanks, the hoses come right out the top along the transom about 2 feet to a T fitting and into the pump. I only run 1 tank at a time using valves at the tank. Im having flow problems, sometimes none. This seemed like a good way to go what am I missing. is the pump not able to pull from the tank ? seems like a very short run. what if I run the hose along the bottom then up to the pump will it then siphon properly. Im lost how should I have run this.

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    S&S
    S&S is offline
    Steve S&S's Avatar
    Join Date
    May 2011
    Location
    Granite Bay, Ca
    Posts
    400

    Default

    I would try mounting fuel pump lower, maybe along side of pump bowl on transom or along side a stringer. I've always tried to keep fuel pumps as low as possible in relation to fuel tanks. Check and make sure you have a good ground as well.

  4. #3
    Senior Member
    Join Date
    Feb 2012
    Location
    OC, CA
    Posts
    359

    Default

    Quote Originally Posted by sox View Post
    Just installed a holley electric fuel pump in my 73' tahiti jet. I mounted it to the transom just above the jet bowl. Its being fed by 2 side tanks, the hoses come right out the top along the transom about 2 feet to a T fitting and into the pump. I only run 1 tank at a time using valves at the tank. Im having flow problems, sometimes none. This seemed like a good way to go what am I missing. is the pump not able to pull from the tank ? seems like a very short run. what if I run the hose along the bottom then up to the pump will it then siphon properly. Im lost how should I have run this.
    Electric fuel pumps are pushers and not pullers with the exception of Weldon. It needs to be primed to push the fuel to the carb. You need to lower the pump as low as possible to the tanks, to allow gravity to feed it and prime it.

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Senior Member CP598's Avatar
    Join Date
    Sep 2008
    Posts
    262

    Default

    Quote Originally Posted by Ol Blue View Post
    Electric fuel pumps are pushers and not pullers with the exception of Weldon. It needs to be primed to push the fuel to the carb. You need to lower the pump as low as possible to the tanks, to allow gravity to feed it and prime it.
    As stated, electric pumps push better than they pull. Ideally the tanks would have the outlet in the bottom, and the pump mounted below the outlet.

  7. #5
    Living in a cage of fear thatguy's Avatar
    Join Date
    May 2008
    Location
    Redding, CA
    Posts
    16,461

    Default

    You need to lower the pump.
    I have a blue, it is mounted on a stringer, 2 side tanks T in just like yours then goes down a single line to the pump, which sits by the jet unit on a stringer.
    Tommy
    Quote Originally Posted by Rexone View Post
    Tommy please remove all Jimsplace quotes from your sig and don't put more back. He doesn't like it and it is against the rules. Thank you.
    "So as through a glass, and darkly
    The age long strife I see
    Where I fought in many guises,
    Many names, but always me."

    Gen. George S Patton

  8. #6
    sox
    sox is offline
    Junior Member
    Join Date
    Jul 2012
    Posts
    2

    Default

    Thanks guys. You are confirming all of my thoughts. My concern with mounting it down low on a stringer is all the water that splashes back there. Is this a concern or can the fuel pump take being in some water from time to time.
    thanks again for the replies, very helpfull.

  9. #7
    I'm No Expert Shaun's Avatar
    Join Date
    Feb 2008
    Location
    San Clemente, Ca
    Posts
    3,139

    Default

    I've never understood all this talk about needing to mount a pump low so that gravity will feed it. My pump is mounted below my tanks but i run a filter/water separator up on the transom above the jetpump, above the fuel tanks. So my pump has to pump the fuel up the tank straw, across the transom, fill the fuel water/filter separator and then down to the pump. I've run Mallorys pumps like this for 15+ years, and now this year i just changed to an Aeromotive pump and I have never had a problem. Even if I change my filter or drain the system the pump never has had a problem pulling fuel.

    I think your problem is else where personally, mounting your pump/lines/filter/whatever lower may band-aid the problem but something just doesn't seam right. That's just my opinion, i'm no expert.

  10. #8
    Senior Member
    Join Date
    Feb 2012
    Location
    OC, CA
    Posts
    359

    Default

    Quote Originally Posted by sox View Post
    Thanks guys. You are confirming all of my thoughts. My concern with mounting it down low on a stringer is all the water that splashes back there. Is this a concern or can the fuel pump take being in some water from time to time.
    thanks again for the replies, very helpfull.
    I put my relay & circuit breaker kit in a small box to keep it from getting wet.

  11. #9
    Senior Member
    Join Date
    Feb 2012
    Location
    OC, CA
    Posts
    359

    Default

    Quote Originally Posted by Shaun View Post
    I've never understood all this talk about needing to mount a pump low so that gravity will feed it. My pump is mounted below my tanks but i run a filter/water separator up on the transom above the jetpump, above the fuel tanks. So my pump has to pump the fuel up the tank straw, across the transom, fill the fuel water/filter separator and then down to the pump. I've run Mallorys pumps like this for 15+ years, and now this year i just changed to an Aeromotive pump and I have never had a problem. Even if I change my filter or drain the system the pump never has had a problem pulling fuel.

    I think your problem is else where personally, mounting your pump/lines/filter/whatever lower may band-aid the problem but something just doesn't seam right. That's just my opinion, i'm no expert.
    Shaun, Weldon says you can mount a Weldon pump on top of a fuel tank and it will pump. None of the other Mfgs will say that including Aeromotive.

  12. #10
    I'm No Expert Shaun's Avatar
    Join Date
    Feb 2008
    Location
    San Clemente, Ca
    Posts
    3,139

    Default

    Quote Originally Posted by Ol Blue View Post
    Shaun, Weldon says you can mount a Weldon pump on top of a fuel tank and it will pump. None of the other Mfgs will say that including Aeromotive.
    I'm not saying they do, I'm sure that's probably the first words out of their mouth when you call them for help. Just like the first words out of MSD is "You have to be directly connected to the battery". Point being they work regardless, least in my experience. My pump when the system is dry can get fuel all the way to my bowls with in seconds. I just think it's a crap answer that's all, but I could be wrong.

  13. #11
    Senior Member MBMoseBilt's Avatar
    Join Date
    Apr 2008
    Posts
    132

    Default

    Quote Originally Posted by Shaun View Post
    I've never understood all this talk about needing to mount a pump low so that gravity will feed it. My pump is mounted below my tanks but i run a filter/water separator up on the transom above the jetpump, above the fuel tanks. So my pump has to pump the fuel up the tank straw, across the transom, fill the fuel water/filter separator and then down to the pump. I've run Mallorys pumps like this for 15+ years, and now this year i just changed to an Aeromotive pump and I have never had a problem. Even if I change my filter or drain the system the pump never has had a problem pulling fuel.

    I think your problem is else where personally, mounting your pump/lines/filter/whatever lower may band-aid the problem but something just doesn't seam right. That's just my opinion, i'm no expert.
    It's not a gravity feed it a siphon effect. Always try to place the pump below the tank pickup.


    Sent from my iPhone using Tapatalk

  14. #12
    83 Crusader - 468 BBC SNiC's Avatar
    Join Date
    Apr 2011
    Location
    Sweet Home Alabama
    Posts
    2,525

    Default

    Quote Originally Posted by sox View Post
    .. I only run 1 tank at a time using valves at the tank....
    I eliminated the valve, and just use a "T" and pull from both tanks simultaneously, thus keeping the weight equally distributed. Works well.
    FYI, I have my Mallory fuel pump mounted on the inside of my stringer, no issues
    Last edited by SNiC; 07-08-2012 at 06:13 AM.



  15. #13
    Senior Member MBMoseBilt's Avatar
    Join Date
    Apr 2008
    Posts
    132

    Default

    The shut off valves need to be t the Tee not the tanks.


    Sent from my iPhone using Tapatalk

  16. #14
    senior member turbo wog's Avatar
    Join Date
    Mar 2008
    Location
    sacramento
    Posts
    1,814

    Default

    how old is your pump? i never got much life out of a holley before they were crap! not predudice against holley just hate them 'cause of all the first hand premature falures ! i got a 1 1/2 - 2 yrs on a part time camping van. completly waisted ..i pulled it apart & it was toast. worn out severly. every single yr needed a new one on my boat. i went to mallory. i got 1 season or 2 & the seal leaks ,needs to be rebuilt. .....anyway just thought you might like to know some of the problems you could be facing if its not brand spanking new.......oh & old switches could not be making a good contact for the electrical & even the brand new "china" switches suck. took one apart because i was desparate to get running & the new one was missing parts inside . i took the old one apart too to find this out. one more thing! my brand new malory wasn't pulling either ! the wires on the pump were backwards!!!!!! i wired the black to hot & red to ground & the pump started working!!! its still on the boat!! gotta send it back ,the new one already came.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	P1000657.jpg 
Views:	28 
Size:	95.8 KB 
ID:	168084  
    Last edited by turbo wog; 07-08-2012 at 12:28 AM.

+ Reply to Thread
Page 1 of 2 1 2 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in


Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95