2006 225hp Mercury Optimax wiring schematic question, crazy beeps, and shop manual

[potomaccreekdweller]

Serial no. 1B388124, 2003 Gambler Intimidator 2
Alright folks, I have a 2006 225 Optimax that has been giving me some issues. It will start fine and purrs like an Opti does but it will start a continuous alarm with the fuel lift pump pulsing on and off after a few minutes-at first it only did this when I hit large waves and now it will not run long enough to get on plane most times. Smartcraft shows the temperature never gets higher than 125ish, peeing good, oiling good. I have a suspicion that it's electrical related so I started going through all the wiring today. I noticed that the grounds on the coil pack rail were all dirty, also cleaned the rest of the chassis grounds on the motor. Going to test it tomorrow
Something else I noticed was the yellow wire with a spiral white stripe corroded off on the female end of the plug on the starboard side. I used the volt meter to determine that it goes to pin number 8 on the lowest plug on the ECU. Can anyone tell me what this goes to on the motor? I bought a service manual that was supposed to cover all OPtimax years but only goes to 2001 and the schematic in it does not align with my wiring harness on the 06.

I've googled a lot but have not had much success in finding a full service manual for this motor. I definitely find Opti manuals but it doesn't say what years it covers. Any suggestions would be appreciated but I would liek a pdf manual

[SilverFox579]

The correct service manual for your engine can be obtained from any Mercury dealer with your engine serial number as Mercury does not use "years". I recommend contacting board sponsor European Marine - If you want to order or price Mercury Engine Parts or Accessories

[EuropeanAM]

+1

Don't bother with the Google Library for this- you'll probably "get" something, but it may not be very helpful.

The only solid yellow wire in the bottom PCM plug is on Pin# 3. That wire COMES FROM the MAP sensor (it's the reference/return wire).

[potomaccreekdweller]

Still having the same issues, but now the power relay and fuel pump are flicking on and off with the ignition key off. To trigger it to do this I key the ignition switch to the on position and turn it off, the power relay and fuel pump keep pulsing on and off. Upon disconnecting the ignition switch harness at the motor, and arcing the two studs on the main solenoid I'm unable to get it to repeat. Going to replace the ignition switch tomorrow. If that doesn't fix it I guess I'll send the PCM off to get reworked by
Appreciate the responses but the yellow wire I'm talking about is not the one that goes to Pin #3, it definitely goes to Pin #8 on the lowest plug. Here's a picture of it.

IMG_0416 (1) y wire opti.jpeg

[lpugh]

I think the wire in question goes to the trim sensor , Are you sure about that serial number? 0T599000-1B226999 agrees with pin 8

[potomaccreekdweller]

Yeah I confirmed that the serial number was correct.
If that wire does go to the trim sensor then it would have no affect on the issues I’ve noted above. The trim sending unit has been broken since I got the motor in 13’ with 50 hrs on it.
The new ignition should show up today. If that doesn’t resolve this then I’ll be shipping the PCM off

[Johnny Ray]

Hope this will help. I have a 2007 Pro XS that I just replaced the neutral safety switch. Mine started and idled with no problem all through 5 or 6 trips while finding my problem. Mine started missing on take off, then would run fine. Then started missing while running. Took it to dealer and could not find any issues. The switch finally went completely out and the motor would not get over 3000rpm while pulsating and horn going off with short beeps. Once the switch went out, the issue was found. I unplugged the switch on the water and it ran just fine. If this is the same problem you have, unplug the switch and see what happens.

[lpugh]

Hope this will help. I have a 2007 Pro XS that I just replaced the neutral safety switch. Mine started and idled with no problem all through 5 or 6 trips while finding my problem. Mine started missing on take off, then would run fine. Then started missing while running. Took it to dealer and could not find any issues. The switch finally went completely out and the motor would not get over 3000rpm while pulsating and horn going off with short beeps. Once the switch went out, the issue was found. I unplugged the switch on the water and it ran just fine. If this is the same problem you have, unplug the switch and see what happens.

I think you are referring to the interrupt switch under the cowl which is not a neutral safety switch

[Johnny Ray]

Sorry for the confusion then. It is the switch that bolts to the shift cable and tells the computer if the motor is in neutral or not.

[lpugh]

Yes Sir, limits RPM in neutral and informs PCM of shifting to momentarily reduce engine torque for smoother shifting, His symptoms are not the same as this switch failing.
Voltage tests of the ignition switch (input and output), master power relay and cannon plug are in order I think, As well as all power and grounds ckts

[EuropeanAM]

Technically the switch on the shift slide is a "shift position switch". It simply signals IN GEAR or NEUTRAL to the PCM (and the PCM is what takes actions based on the INPUT from the switch).

[potomaccreekdweller]

Appreciate the responses. I tested the neutral safety switch with a MM, it checked out in all positions during my toubleshooting.
Simons called me yesterday and there are several issues with the PCM causing the power pins to short to ground and provide power all the time. They are going to attempt to repair it and let me know what happens. I guess I should just be happy that I was close to the motor when I noticed the fuel pump pulsing on and off without the ignition switch on, and that I use a master power cut off switch at the battery. Could have been a nice crisp Gambler Intimidator 2