2000 Mercury 150 EFI ECU Failure

[Bushman244]

I just bought a 2000 150 EFI. Boat runs great off trailer, once I’ve run it for about 10 mins I go to idle. Then go wot it only gets to 2000 RPM. If I leave it WOT after 1-3 mins it will come alive and run great. But it does this all day. I have replaced all fuel lines from tank to fuel pump. New mechanical fuel pump, new electric fuel pump. I have a clear inline filter that I set up I am sure it’s getting fuel flow. I had some questionable wiring on trigger so it got replaced too. Tested stator it’s good and is charging while running. Replaced plugs with new proper plus for engine. Had compression check done all passed. It’s at shop now and tech said it looks to be the ECU cutting in and out. But is looking for a ECU to install to test before he’s sure. Sound about right any other suggestions. I am a mechanic my self and have looked over everything wiring all looks good. Just hate to throw $$$$ at it. Oh and it only does it under load.

[wentbroketryingtogopro]

I know the feeling.I had a 2000 175 efi that started doing the same thing in may 2014.I was throwing money at it left and right.Plus I had taken it to three different merc techs in three different states that could not diagnose the problem.I ended up selling it to a guy that lived on ky lake.He took it to a tech there on ky lake and they ended up having the ECU rebuilt and had the injectors recalibrated and cleaned.He said that took care of the problem.Don Weed will probably chime in and give you his take on it.You made need to post your engines serial number.Thanks and good luck.

[bassnman81]

http://www.simonmotorsports.com/

[JOE54]

very possible injector driver bad, would be nice to try another to confirm, doesn't have to be 150 ecu just for test

[Bushman244]

ECU fixed issues. Had to use one off 175. But now working

[EuropeanAM]

Get the correct one repaired so you're not running your engine rich all the time.

For future reference, your engine is a 2.5L (next forum down the list for best results).