2010 mercury pro xs 175 beeps. Help

[Bradcal]

I start the engine and it runs fine. After 10 seconds it starts to beep every second. Beep beep beep and it will not stop. It has put itself in guardian mode.

Background...
Compressor went out and i replaced it. Cleaned out the hoses and injectors. Motor ran great. Brought it home and put in a new impeller and then went to the lake to run it. It then started the beeping. I took it to a mercury mechanic and he put it on the computer and it had no faults. I bring it home and it still beeps after 10 seconds of running.

I need advise. Please help me. What can be going wrong with it?

[EuropeanAM]

If you would, please take a moment to review the Announcements at the top of the Forum, and provide the Required Info each time you post. Thanks!

Also good idea to clarify the alarm sequence. A Solid Tone, or 4-beeps, Pause, Four beeps.

[Bradcal]

1B765115 is the serial number. Sry about that

[JOE54]

there will be faults stored if warning horn is activated

[Bradcal]

I found that I have a bad air injector. This should be corrected soon and i hope all will be fixed.

[Rickp]

A bad air injector will not set an alarm, make sure your engine oil tank is full.
Also could be water in fuel.

[EuropeanAM]

A bad air injector will not set an alarm, make sure your engine oil tank is full.
Also could be water in fuel.

Not necessarily accurate. Shorted or open circuit WILL set a fault (and that can occur inside the DI, or in the wiring harness between the PCM and the DI).

[Bradcal]

It was the air injector on the #3 cylinder. I replaced it and all is well. I have taken it out twice and it is running like it should.

Side note...these pro xs engines are stout. Not like the old 175 merc i used to have.

[JOE54]

much stronger comparable to 200 2,5 efi