formula370ss

I'm having a problem with the fuel pump on my motor cutting off. I first thought it was my kill switch so I by-passed it and the problem still occured. I also changed out the relay mounted near the ECU on the motor that controls the fuel pump and still no luck. It can happen when I'm simply trying to start the boat and it has also has cut off on me twice when I was running across the bay. Has anybody come across this problem before ???

stevesxm

the pump runs for 10 sec when you turn the key on and then times out. the ecu senses engine cranking and trips the pump relay back on as long as the motor is running.

so...

either the pump is bad .... possible.... hot wire it to a switch and try running it that way the next time you go out. i ve had them stall from trash and rust and cleaning them and running wd 40 thru them saved them...

or the relay is bad... possible again and cheap to change...

or the ecu has lost that signal altho thats the crank sensor and it wouldn't run at all without that...

and i presume you are talking about the hi press pump in the cool fuel housing... right ?

formula370ss

yep. It does cycle for a few seconds when I turn the key. That is what I listen for when I fire that motor. When I don't hear it I know the problem is back. It shut down on me saturday when I was actually cruising along at 3800rpm's. I fooled with the by-passed kill switch wires and got nothing. I switched out the relay and got nothing and then after about 6 or 7 starting attempts I heard the fuel pump activate and the motor fired up and I didn't have any more problems with it the rest of the weekend . SoI still don't know what I did or touched to get it to work again. That seems to be the case all the other times it's happened as well. ?????

stevesxm

when i first bought my boat , the 502's like yours that i put in had been sitting for several months. when i got it all hooked up the pumps wouldn't run. so i tapped them and they did and everything was fine except that they would both do what yours do. so i took them out and rattled them apart and there were flakes of rust floating around. these pumps have zero internal clearences and no torque. anything at all will stall or stick them. what i did was clean them throughly, low hi press air thru them and then let them run continously for an hour just recirculating wd 40 to clean out any hidden rust and to polish up the rotors a bit. after that they never gave me a whit of trouble and thats been going on 3 years now.

formula370ss

how hard are they to remove. I know where they are located but they look like they connected to some other pumps as well ????