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1999 Merc 150 EFI will not idle

D

darrryl

New member
I purchased this boat knowing one piston was melted. I rebuilt the engine with OE Merc piston and ring sets on all holes. Good compression now. Sent the injectors out for complete rebuild and balance. Turns out #6 injector was bad and that was the piston that burnt. All back together and I have check and double checked everything I can see. It starts if you move the lever forward to advance the throttle. Run rough but on all cylinders. All cylinders warm up about the same. As soon as I pull the throttle back to idle it stalls. Will not idle at all. Seems to rev up fine. Have not been in the lake yet to see what the power is like.
Any ideas out there?? That little red light never flashes on the front of the engine?? How do I get codes out?? What should the fuel pressure be?
Thank you anyone that may be able to help with this.
 
Run a cylinder drop test, Pulling one plug at a time to find possible issue. Cylinder that does not drop is your problem, Lack of fuel or spark, If no spark,run an open air gap spark test,you should see a lightning blue snapping audible spark
 
After more investigation I discovered there is two 4-cavity electrical plugs that are identical and near the throttle body. They are interchangeable and that is what I had done. I switched those two plugs around and it now idles. Thanks everyone for the replies and reading this issue.
 
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