No power at fuel pump

[alldodge]

My wife isn't green

:noidea:

I dont hear pump with key on either

It shouldn't with the fuse blown

Did you see my post #16 ?

 

[aparisi59]

where the red probe is, i have 12

 

[alldodge]

It appears from the look of the back of the plastic has gotten hot, probably from the relay.

If you can jump between the two points without the relay installed, and the fuel pump fuse installed, and it does not blow the fuse then the relay is the problem

 

[aparisi59]

not sure if i follow the relay u posted

 

[aparisi59]

i swapped relays from the other motor. nothing changed

 

[alldodge]

i swapped relays from the other motor. nothing changed

Now, I'm not following.
My understanding is the fuse going to the pump was blown.
Replaced the fuse and turning the key it blew again
Jumping a wire from the battery to someplace which would power the pump, the wire got real hot.

I assumed that the relay was not removed when the jumper wire was used, this is the reason I'm thinking maybe the relay was shorted out

Your first post listed the relays where swapped but had no effect, but then later posting said the fuse was blown and when a jumped the wire got hot.

Just trying to figure out where the fuse gets blown.

Running the pump on the bench is under no load and I'm guessing here, it also is not powered up using a inline fuse.

Could be your pump is just bad.

Could swap the pump from the other motor to verify, but trying to figure an way of finding problem without taking the other motor APART

 

[aparisi59]

i am far from my boat now. but i will swap pumps from engine to engine to see if theres a change. i did test the pump on a bench. runs with 12 volts from a batter charger connected to it. .003 ohms going from positive to neg. and no continuity from the housing to either pintles on the connector

 

[aparisi59]

the jumper went from the battery straight to the positive of the pump. and it got really hot. it was a speaker wire. and got so hot it burnt my finger. on the bench, i used thicker gaged wire. no real load, the wire didn't get hot. i guess i have to wait till tomorrow and swap pumps and see what happens.

 

[alldodge]

My guess is your pump is bad, the ,003 amps is low for any motor but needs to be tested

You could just connect the original pump thru the fuse (or thru a voltmeter set on amps) and if it blows the fuse or draws more then 7 amps, its the pump

 

[aparisi59]

ok so red wire is hot all times. black is ground. yellow goes to pump. and the two wires together must go to ignition and alt....right???well i don't have 12v with key on on the two wire. so i have to trace that two wire.

 

[alldodge]

Black goes to ground, but the other two wires are: 1 goes to the alternator and 2 goes to the starting circuit. Both the two wires have diodes in line with them

 

[aparisi59]

Tested on bench again w dvom pump drew about 3 amps before my cheap craftsman meter decided to not read amps anymore I would say about 4 seconds of running

 

[Bt Doctur]

You wont have 12 volts with the key in the on position.The power to run the pump "during cranking, start position" comes from the yellow wire thru the diode to close the relay contacts. Once the motor is running the alt supplies the power to operate the relay`s coil thru it`s diode.
If you bench test the pump it should not draw more than the 7.5 amps ,if it does the pump is defective. If you unplug the pump and replace the blown fuse and then turn the key to "start" ,then see if the fuse is blown. If it is you have a relay socket short.You can replace that relay and socket with one from a GM Chevy blazer fuel pump relay.Amp rating is higher for the contacts and comes in a waterproof housing.

 

[Bt Doctur]

 

[aparisi59]

ok so made some gains today. swapped fuel pump from starboard motor and some good luck. didn't blow a fuse. BUT. starboard side when key is turned to on, and NOT cranking u can here the pump whirl . but not the port. from my understanding was when the key is on but not cranking, u can here the pump. so one side is not function correctly. the pump was bad. i will be ordering a new pump.both engines will start .regardless if the pump spins before cranking ,PROBABLY because the carb holds fuel and after it starts the alt kicks in and the pump goes on. if the pump isn't supposed to be working with key in the on position, not turning over, then theres something wrong with the starboard.

 

[alldodge]

When the key is turned to ON, the fuel pump will not run because the alternator is not supplying power.

When the key is turned to start and the motor starts turning over, power is supplied to the pump. Once started, the ALT produces power and keeps the pump running.