1996 mercuriser 7.4 still no spark
#13
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replaced both relays and oil pressure sensor also , no spark still , then i unpluged the relays and pulled on the wires unpluged the ecm , pluged it back in and it started ran perfect for one min and tryed to quit , so i restarted it again and it quit again after about a min , so i started it and when i tryed to quit i started pulling on wires and it stayed running ten minutes , so i tryed to get it to quit by pulling on the same wires as before didnt quit so i started to mess witht the pigtail that goes to the vst elect pump and when i kinked the wires it died , so started the motor again stayed runnning so i messed with the wires again and it died again , now wont start again no spark, also i checked the fuel pump wires with an ohm meter and they checked out fine , i dont get it , anyone have any other things i can check and by the way the Dist checks out fine
#14
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Joined: May 2007
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From: On a Boat
pull the fuses and inspect each socket for signs of heat distortion or corrosion, do the same for the relay sockets. I have seen where corrosion causes high resistance and burnt connectors and melted wire at the fuse block and relay socket connectors.
You might hunt for a harness take off for an early 454 or 502 with VST, they are the same and shouldn't be much.
You might hunt for a harness take off for an early 454 or 502 with VST, they are the same and shouldn't be much.
#15
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From: dallas tx.
pull your connectors apart and look for cracked plastic inside the plugs, they can sometimes ground each other out,,,you can also disconnect the plugs by a few inches,and run jump wires between each connector,,this worked years ago on a car engine no one could figure out
#16
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From: On a Boat
#18
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Spark now , took out Dist and took it to a dyno shop and had them test it , it had no spark they told me the pickup coil was bad , so we they took a closer look at it and the green wire came out of the coil so the connection was bad , they said that explanes the inntermitted spark , so going to put it back in today , that was a new pickup coil from mercruiser , crossing my fingers will up date tomorrow and thanks again for all the help



