2006 Optimax 225 Guardian Mode

[Ventura]

Hi, I’m new to this forum and have been scouring this forum and the service manual for help with this problem. Thank you in advance for what you’ve contributed and for helping with my issue described in this post.

I recently repowered my 20ft Whaler with a rebuilt 2006 225hp Optimax on a 17p prop. I’ve had trouble getting the mechanic who rebuilt this for me to diagnose the problem and to honor his warranty. His DDT scan sees the occurrence of this “over rev” fault but says everything is normal after he replaced the TPS. He also claimed to have tested the boat in a lake, but I know is not true (lack of gas use and increase of engine hours). With him dodging my calls, I’ve taken it upon myself to repair and hope to get some advice here.

I am intermittently going into Guardian mode, a few times per trip, four total trips so far. The occurrence seems random and is not readily reproducible. I get a long 4 second beep and a check engine light. After slowing down, it goes away and I can then resume as if nothing happened. I don’t have smartcraft, but Vesselview mobile tells me error code 2011-23, “Guardian, A particular state or condition exists, Engine guardian is active, Power will be limited to prevent engine damage, Reduce engine speed.” I get no other relevant faults. My voltage ranges from 13.5V to 14.5V. Water temperature is around 120F, as reported by Vesselview.

For various reasons, here’s what I’ve done so far to fix this outboard:

1. New alternator. Mechanic gave me motor with a broken one...
2. New Optima blue top D31M, 900CCA. New 20ft 1/0AWG cable runs to help with cranking/staring issues.
3. New TPS (although old one was probably fine), measured 0.5V to 4.7V at idle to WOT.
4. New key switch control harness. Old one was spliced into the factory Evinrude harness and I had intermittent connectivity on the purple ignition wire.
5. Outboard oil tank is full and switch measures closed.

I’m a bit lost on what to look at next, short of taking it to a dealer. I do plan to look at the shift position switch next. Any ideas or suggestions?

Edit (5/3/21):
1. Engine Serial Number: 1B242084
2. Year/Make/Model: 2006 Mercury Opitmax 225XL
3. Prop you are Running: 17P Mirage Plus, 44mph @ 5200RPM (boat is a 20' Boston Whaler Ventura, ~4000 lbs. loaded)
4. Current Maximum RPM: 5200
5. Idle and WOT Water Pressure Readings: Unknown, not sure how to get this info
6. Smartcraft or Analog Instruments?: Analog, with VesselView Mobile

[Bryanmc57]

What are the rpms when this happens? A 17 pitch prop sounds way too small for your application so an overspeed sounds likely. Also, you need to add your serial number to your post.

[SilverFox579]

Welcome to BBC! Please take a few minutes to read Announcement at top of forum and provide engine serial number - PLEASE READ Before Posting

This is fastest way to sharpen diagnostic efforts - WARNING HORN "BEEPED"

[Ventura]

Thank you for the responses and apologies for the missing information. I've added my engine information to the top post and below.

The motor started with a 19P prop, but that kept me at 4800 RPM and 40 mph. This lead me to switch to a 17P, which got me to 5200 RPM and 44 mph.

Guardian mode seems to kick in at random times. It has happened while I was cruising between 3500-5000 RPM and while advancing throttle to get on plane.

1. Engine Serial Number: 1B242084
2. Year/Make/Model: 2006 Mercury Opitmax 225XL
3. Prop you are Running: 17P Mirage Plus, 44mph @ 5200RPM (boat is a 20' Boston Whaler Ventura, ~4000 lbs. loaded)
4. Current Maximum RPM: 5200
5. Idle and WOT Water Pressure Readings: Unknown, not sure how to get this info
6. Smartcraft or Analog Instruments?: Analog, with VesselView Mobile

[SilverFox579]

VesselView Mobile will provide water pressure and/or coolant temp and gets info from engine computer (PCM). This is accurate data you can trust for water pressure, coolant temp, and more.

Your engine's horn strategy is described in FAQ topic, a solid tone is a critical alarm and the fact Guardian is activating shows it's trying to prevent damage from whatever the condition is. I suggest you find a dealer that can connect to your engine, provide you with printouts of stored data and post them here. Without that we'd just be guessing.

[EuropeanAM]

May seem off in left field- but let's check it:

Inspect the SHIFT CABLE where it attaches to the shift slide bracket. The NUT should be snugged and then backed off 3/4-1 turn so that the nylon washer will rotate FREELY under the nut. The slide should not be slathered up in a bunch of grease (acceptable to have a very light coating only).

Either above item can cause the SHIFT POSITION SWITCH to hang up or malfunction. If suspect, for TESTING PURPOSES ONLY, you could unplug that switch (under port side rail/head) to see if you can then accelerate normally without Guardian.

If so... replace the shift position switch, paying special attention to the above recommendations.

[Ventura]

Thank you SilverFox and EuropeanAM for your advice.

If my next few attempts don't work, I will take this to a dealer. It will take me a few weeks to get the parts, install and do a trial run. I have a shift switch and impeller kit on order to install. I'll also inspect/adjust the shift linkage as suggested. Thank you!

I am new to Vesselview and am not sure what I can trust as I'm not sure what "optional" sensors it may be looking at. I've managed to pull some screenshots, that do point to a possible water pressure problem. For some reason, I did not notice the water pressure fault when it happened. It also only showed up once while I had many guardian faults. I also ignored the 0 water psi, assuming it was an "optional" sensor. Should I be concerned about the 0 oil psi? I vaguely remember these two had *asterisks as "optional" sensors in the app.


guardian.jpgwater_pressure.jpgdata.jpg

[SilverFox579]

You can ignore oil pressure and oil temperature, neither are used with the Optimax. I think your coolant temp would have been MUCH higher than 120° with 0 water pressure at 5krpm and suspect you may have a sensor or wiring issue. Wait and see what Don or Joe54 have to share...

[Ventura]

Thanks SilverFox. I'll investigate the water pressure sensor as well.

After thinking more about my prop pitch of 17P, which I changed to because I was limited to 4800 RPM at WOT on a 19P. I now wonder if my shift linkage isn't adjusted correctly and I don't actually get to WOT. I'll look at this as well.

[EuropeanAM]

Might need to check the Block Pressure Sensor. Water pressure is a STANDARD FEATURE on Optimax engines: Your VV Mobile Fault shows that there is a problem with low water pressure.

Gray tubing attaches to the block pressure sensor at the top of the coil plate (back of engine). Simple legris-type fitting connection, can disconnect and check at idle to see if water is flowing from that tube.

I would recommend addressing THIS fault as if it were the ONLY problem currently. Always start with the most current and obvious problem, before searching for something more "obscure".

[Ventura]

Thanks EuropeanAM. It does seem like the Block Pressure sensor is the most likely culprit and/or the water pump. It will take me a few weeks to get to it, fix and test, but I will report back as soon as I have news. Thanks again everyone!

[Ventura]

I managed to get to the boat yard to take a look with DIACOM diagnostic software.

1. Shift switch seems to work fine, but it could be intermittent. Part still hasn't arrived yet.

2. With the throttle control fully forward, there's still ~1/8" of play going toward WOT on the throttle body lever. It seems I need to adjust this.

3. I have zero block pressure at idle and 1100 RPM. I didn't feel comfortable running higher since I'm on land running on ear muffs. There is water coming out of the pressure sensor hose when I disconnect it. The cable connection looks secure. I have a replacement sensor on order. Power Limit Setpoint is 42%, possibly because of zero block pressure?


opti1.jpgopti3.jpgopti2.jpg

[JOE54]

1/8 in play not gonna be problem , sounds as power limit is report back after sensor replaced ,possible base gaskets (2) leaking under powerhead

[EuropeanAM]

I'm going to suggest that you also plan to replace the Water Pump, just to be safe.

[Ventura]

I got a new block pressure sensor and new water pump installed. Now I get 0.8-1.2 PSI reading at idle on ear muffs. Next week, I’ll try to get it on the water for a real test.

[EuropeanAM]

You did have the low water inlets covered, right?

[Ventura]

I finally got a sea trial in with a new block pressure sensor and water pump. Got up to 10 psi at 3100 rpm. Too rough to go any faster, but it runs well now without going into guardian mode. Thanks for everyone’s help.

[SilverFox579]

What was your idle water pressure after launching?

[Ventura]

You did have the low water inlets covered, right?

No, I didn’t have the front inlets covered. I guess thsi could have let in air and cause reduced or erratic pressure.

[Ventura]

What was your idle water pressure after launching?

I think it was about 2.5-3 psi while idling.