Like Tree0Likes

power for electric fuel pumps ?

Reply
Old 12-23-2004, 06:41 AM
  #1
Registered
Thread Starter
 
Join Date: Mar 2004
Posts: 211
Cool power for electric fuel pumps ?

Hey guys im drawing from my coil for my electric fuel pumps. 12 volts. Is this the wrong power source? Could this cause a week ignition ?
boatman747 is offline  
Reply With Quote
Old 12-23-2004, 06:53 AM
  #2
Ginger or Mary Ann?
Charter Member
Trade Score: (1)
 
US1 Fountain's Avatar
 
Join Date: Oct 2000
Location: Lafayette. IN
Posts: 10,843
Default Re: power for electric fuel pumps ?

Is the 12v wire going to the coil able to handle the extra load on it now? If anything, I would think a relay that got it's signal from the coil would be better. Thus allowing you to pull a dedicated lead for the pumps from elsewhere.

Last edited by US1 Fountain; 12-23-2004 at 06:55 AM.
US1 Fountain is offline  
Reply With Quote
Old 12-23-2004, 07:02 AM
  #3
Registered
 
Join Date: Nov 2000
Location: Westport, Kentucky
My Boats: Baja Force 235
Posts: 1,282
Default Re: power for electric fuel pumps ?

Yes. Here is what I did. Use a pressure switch that makes when you have oil pressure. Feed it with 12 volts and use the output to fire a relay that will switch a good power source to the fuel pump. Lose oil pressure or someone turns the key on you have no fuel pump. If need be you can jump the pressure switch to fill the float bowl but this has never been a problem for me. There are pressure switches that will only make when cranking or when there is enough pressure to close them. In any case use a relay to source good power to the pump.
BadDog is offline  
Reply With Quote
Old 12-23-2004, 07:30 AM
  #4
Registered
Trade Score: (1)
 
Biggus's Avatar
 
Join Date: Apr 2001
Location: Naples, Maine
My Boats: 02 Cigarette Mystique T/S
Posts: 6,298
Default Re: power for electric fuel pumps ?

I went to electric fuel pumps last summer. When I connected them up I did the same and took power from the purple wire at the coil. I burned out both pumps within a 1/2 hr. It was an expensive lesson...

The best way is with a relay and direct power from the battery.
Biggus is offline  
Reply With Quote
Old 12-23-2004, 08:35 AM
  #5
Registered
 
Crazyhorse's Avatar
 
Join Date: Jan 2001
Location: Holland MI
My Boats: 38 Cigarette flat-deck
Posts: 3,140
Default Re: power for electric fuel pumps ?

Kurt, you should really be running the pumps from contuous-duty relays or solenoids, along with an oil pressure switch wired with a starter bypass.
When I bought my Cigarette the pumps were wired to the positive coil post on the Thunderbolt ignition and I had intermittent ignition operation a few times.
Crazyhorse is offline  
Reply With Quote
Old 12-23-2004, 09:01 AM
  #6
Charter Member
Charter Member
Trade Score: (1)
 
Ted G's Avatar
 
Join Date: Jan 2001
Location: Edgerock Baby!!
My Boats: Marlago 35 FS, 18 Neptune CC
Posts: 7,661
Default Re: power for electric fuel pumps ?

Yup, never hook to the coil for power, the coil or the fuel pump will die a horrible death-and quickly too. A relay and a pressure switch is the best set up.
__________________
Chesapeake Bay Powerboat Association
www.cbpba.com
Ted G is offline  
Reply With Quote
Old 12-24-2004, 07:10 AM
  #7
Registered
Thread Starter
 
Join Date: Mar 2004
Posts: 211
Default Re: power for electric fuel pumps ?

Where do you draw the power for the relay?
boatman747 is offline  
Reply With Quote
Old 12-24-2004, 08:06 AM
  #8
Registered
 
Crazyhorse's Avatar
 
Join Date: Jan 2001
Location: Holland MI
My Boats: 38 Cigarette flat-deck
Posts: 3,140
Default Re: power for electric fuel pumps ?

Connect the relay directly to the battery or main starter terminal, using a fuse or circuit breaker sized accordingly for the load.
Crazyhorse is offline  
Reply With Quote
Old 12-24-2004, 08:28 AM
  #9
Registered
 
Join Date: Nov 2000
Location: Westport, Kentucky
My Boats: Baja Force 235
Posts: 1,282
Default Re: power for electric fuel pumps ?

Or the common post on your battery switch.
BadDog is offline  
Reply With Quote
Old 12-25-2004, 08:49 PM
  #10
monsta
Guest
 
Posts: n/a
Default Re: power for electric fuel pumps ?

The ignition ( purple) wire should be isolated to only fire a solid state relay( most dependable in the marine environment). The ground for the relay should be tapped into a oil pressure regulated hop switch. Relay primary leads should be of 10 ga. and signal leads of 14ga. all of tinned copper. Figure in your resettable breaker, and you'll have a very efficient and trouble free circuit.
 
Reply With Quote
Reply

Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Andy
General Q & A
9
04-01-2008 04:25 AM
963b
General Q & A
5
04-15-2007 07:37 PM
mark30h
General Q & A
6
10-16-2006 10:48 AM
boatman747
General Q & A
12
12-10-2004 06:45 PM
p4-33
General Q & A
35
02-18-2004 09:52 PM



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 07:45 PM.


Copyright 2011 OffShoreOnly. All rights reserved.