I have a 2006 merc 4 stroke 25 hp efi outboard. Bought it used but it ran fine. I believe they used ethanal fuel in it, i ended up replacing the fuel pickup tube in the tank, it cracked off, i replaced the primer bulb because it split in two. Ran fine, took it to the dock next day and wouldn't start. Took the vst apart, had fuel in it. Low pressure mechanical pump pumps fine. Electric pump in the vst all the plastic and rubber parts were disintegrating. Bench tested the pump and it ran fine. Bought a new pump and installed it because of the bad plastic base and filter. I have no pressure in the fuel rail going to the injectors. Electric pump has voltage going to it when i try to start the motor, but pump wont turn on. A simple test with an ohm meter shows high resitance on the ground side of the pumps plug. If i jumper the pump to ground it turns on. Took the motor to the marina mechanic and they are stumped. They said the ecm is fine, not sure how they tested that. Anyone know what would cause the pump circuit not to ground. I am under the impression that the ecm controls the ground circuit for all the electronics, such as injectors, sensors, ect. Anyone have a clue. If it matters i filled the tank with non ethanol fuel and had added a few ounces of sea foam.
