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View Full Version : Pro Max fuel pump issue 1998 225 EFI.


Enticer1
03-06-2010, 08:23 PM
While running on the hose today the mota stumbled and stalled. I had the cowl off and noticed there was no fuel pressure ( I have a guage on the pump ) I turned the key off and on a few times and noticed the pressure came back up ( 40 lb's ) so I fired er back up and in less than a min. same thing. I then put a meter across the fuel pump leads so I could watch the voltage. Fired back up and in less than a min. the voltage dropped along with the fuel pressure and of course the mota stumbled and died. I have a stock ECU and a Brucato PCU and they both do the same thing. Now I have removed the fuel pump assembly from the mota and put 12 volts across the leads and the pump humms like a bumble bee for as long as I apply the voltage so now I don't think its the pump. Am I chasing an electrical gremlin. HELP
jody504
03-06-2010, 08:59 PM
Check all grounds first off then you can chase it down by going from the pump back to the battery in steps. I had some bad battery cables do what your is doing one time.I don't know how the Burcarru works but the ecu from mercury killes the pump on ground side so if you are not grounding on the pump when checking you may show 12 volt when you don't have it
JR IN JAX
03-08-2010, 08:39 AM
My stock ECU would just drop out the pump, causing it to stall and then when I would restart it, the pump would run again for a short time. I put my Brucatto ACU back on it and the pump runs fine.
jody504
03-08-2010, 08:06 PM
Yes they kill by ground most go out on the fuel thats way alot run the pump on the key switch.You can run the pump if thats the only part of the ecu thats out.You can ground the neg.and run the pump with the purple wire in the harness which is keyed power.
JR IN JAX
03-08-2010, 09:12 PM
Yes they kill by ground most go out on the fuel thats way alot run the pump on the key switch.You can run the pump if thats the only part of the ecu thats out.You can ground the neg.and run the pump with the purple wire in the harness which is keyed power.Thanks for the advice, that will keep me from having to send off my ECU for repair [to keep as a spare].