electric fuel pump
01-18-2002, 08:02 AM
#1
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electric fuel pump
I am istalling electric pump. where can I get power from to turn the pump off and on? some one said I should only have power to electric fuel pump when the motor is pumping oil. if so can I use the oil sender now or does it have to be a different oil sender unit? if new where do I put it?
01-18-2002, 08:17 AM
#2
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Location: Wilmington,De,USA
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Get power from any 12v., fused source that is hot when the key is on. You can run the ground wire for the pump through an old style brake light switch that is N/O and has 2 screw or spade terminals plumbed into the oil pressure sender (add a "T"). Put an extra ground wire with a pushbutton (momentary on) as a bypass to pressurize the fuel system if you wish before starting the engine. The b/l switch I used is General (mfg) #2332. Alternate pn's - S.M.P. PS-126, Borg S-371, Nieh. DR-135K, or Wells PS-115.
There may also be a kit available to do this as well.
[ 01-18-2002: Message edited by: David ]
There may also be a kit available to do this as well.
[ 01-18-2002: Message edited by: David ]
01-18-2002, 08:49 AM
#3
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You want to install a special switch supplied by holley or other marine fule pump supplier. This switch relies on oil pressure to complete a circuit to run the fuel pump. It bypasses this cuircuit when the starter motor is running to supply fuel for start up.
Last item seeing your pump does not have this switch included in the box you may want to check and make sure you pump is marine application.
Last item seeing your pump does not have this switch included in the box you may want to check and make sure you pump is marine application.
01-18-2002, 10:39 AM
#4
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The source for your 12 volts should be thru a solenoid or relay direct from the battery. This is due to relatively large current draw of the pump & also voltage drop because of length of the wire, ex: battery to switch then return to back of boat...vs maybe 3-4 feet using a solenoid/relay. Use the ignition circuit to operate the relay to apply power. Also, use a circuit breaker (seal can type) rater than a fuse. The breaker will auto reset & you won't be left stranded. 
01-18-2002, 07:06 PM
#6
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Strapman:
Straight 12 Volts from your Battery to a Relay (with a circuit breaker in the middle) From the relay go directly to your fuel pump. Ground the relay back to your common ground, Battery neg, or engine block. Find a keyed on/off 12 volt source go through a hobbs pressure switch (to measure oil pressure) to the relay.
With the key on you'll get power to the hobbs switch, as you crank the engine and get oil pressure power will go through the switch, and turn the relay on, turning on your fuel pump.
Straight 12 Volts from your Battery to a Relay (with a circuit breaker in the middle) From the relay go directly to your fuel pump. Ground the relay back to your common ground, Battery neg, or engine block. Find a keyed on/off 12 volt source go through a hobbs pressure switch (to measure oil pressure) to the relay.
With the key on you'll get power to the hobbs switch, as you crank the engine and get oil pressure power will go through the switch, and turn the relay on, turning on your fuel pump.
