BF225 Alarm and loss of power

I have a new to me 26' Hewescraft Alaskan with a 2012 BF225. I took the boat out for the first time and the motor seems to run fine, but a serious lack of power. It took 200 yards to get up on plane and would only go 23 mph. I changed the fuel filters and replaced the intake manifold cover and the IAB control diaphragm because it was corroded and the valve would not open. I replaced the spark plugs as well. I removed 550 lbs of waterlogged foam and the water saturated wood decking.

The motor is still not running right. Full throttle in neutral is only 4000 rpms, but no alarms. Under load the motor runs at 3200-3900 rpms at full throttle. If I back off the throttle at full rpms fast, an alarm goes off, the motor shudders bad and rpms drop to a "Safe Mode?" The alarm is continuous and no lights are showing on the MIL. At speed I can see the green oil light is on, until the alarm sounds. The original owner called a Honda service center and they told him it was a plugged VST fuel filter and sent him a white plastic filter, which I believe is the VST air vent filter from all my research. Can't find the filter in the service manual. After the alarm goes off, I turn off the key and it starts up and runs every time with no alarm.

Any advice where it start now would be greatly appreciated. I live in Dutch Harbor and we do not have any outboard mechanics on the island, so its on me to fix, or mail the motor to Anchorage. Thanks, John

Lots to think about!
Firstly the waterlogged foam would definitely not have been helping so it's good to remove that.
I'm also wondering about whether the prop is the right size/pitch - but there also seems to be an engine problem.
You did right to change the fuel filters - did you do both the low and high pressure filters? The high pressure filter seems to go off in 12 months and can have a detrimental effect on the fuels system.
Have you checked that all 6 cylinders are firing?

Oh, and backing off the throttle quickly from full revs is not the best idea as it can cause water to get into the exhaust system.
I'd also be very wary about running the engine in neutral at 4000rpm

I changed the spark plugs and they all looked exactly the same, dry with a light brown tint, so I assumed they were all firing correctly. I was told the boat was running fine with the prop that is on it now last year. Yes, I changed the LP and HP filters. Any advice on the VST filter? Or whats causing the alarm?

Let's look at a few simple things first...

As metal chicken suggested, first the prop. For comparison, that 26' Hewescraft Alaskan looks about the same size and weight as my 25 ft. '92 C-Hawk, which weighs around 6000 lbs fully loaded with fuel and two adult passengers. My prop is 14.25 X 15 and I get 5800 rpm.

As metal chicken suggested look at the HP fuel filter. These engines are very sensitive to even a slightly clogged HP filter. Drain the VST.

Are you certain all four lights on your key switch console are working? They should all come on briefly when you first activate the key switch,

BUT, getting an alarm and the green oil light going out is not a good sign. Going into SAFE mode with the oil light out is telling you that one of the two oil pressure sensors is activating. Unfortunately, they are in the middle of the engine V and require that you remove one of the heads to get to them. So let's check a few other things first.

1. Obviously, the oil level should be between the two marks on the oil stick with engine level.

2. Pull fault codes. The procedure is here: View attachment Procedure for Getting Fault Codes.pdf. What the codes mean is here: View attachment MIL Fault Codes Scanned.pdf. Record what you get, then clear codes. Run engine again until it alarms, then pull codes again. If you get a code 26 then the problem is with the high pressure oil sensor. If you get a code 26, you will need to fish out the six-pin connector that comes from those four sensors in the engine V and check the contacts. See item 21 at:
https://www.boats.net/catalog/honda...hp/bf225ak3-xca-2007-and-later/cylinder-block

And see the attached picture: View attachment Wires from sensors in V of BF 225.pdf

3. Fuel pressure test. Connect your fuel pressure gauge in the opening for the pressure relief bolt that sits on top of the cover to the HP fuel filter. You will need a 6 mm adapter for your gauge. Spec is 41 to 48 PSI at idle with the vacuum line at the fuel pressure regulator removed and pinched shut.

4. Compression test - spec is around 200 psi on a warm engine. On a cold engine they should be between 155 - 170 depending on how cold it is. There should be no more than a 10% difference between the highest and lowest compression reading. Make sure you have fresh batteries, all plugs removed, kill switch activated, throttle wide open, and crank for 8 to 10 seconds for each cylinder test.

Let is know what you get.

Hopefully others will chime in with additional observations.

Thanks for the responses. HP filter was changed. Might have been the first time. I had to drill out the bolt, it was so corroded and the filter was dark black. I am not sure all four lights are working, but will check when I get home from work this morning. I just found another thread showing how to check the codes with a shunt. I printed off the PDF you gave to know what they are. I'll have to check on the prop size. I'm pretty sure this matches up with the thread of the guy who's motor was throwing a high temp code. I'll let you know what I find when I come back tonight.

OK. So I went to the motor and hooked up the shunt. My MIL only shows the green oil light and a red one directly under the green one, sorry don't remember what the light was. So if I understand correctly, there should be four lights showing and I have two lights out. I pulled out the wire harness and saw that there are quite a few connections that are not connected. I turned on the key switch. It beeped one time and the two lights showing turned off. Nothing flashed. What in the heck do I do now?

You may have a harness problem. When you turn on the key switch you should get two beeps and all four lights should come on briefly and the red alternator light will stay on. When you start the engine, the green oil light should come on and the alternator light should go off. Verify that is happening. If not, then you may have a harness problem. Replace it because it is not worth the time and effort to troubleshoot it.

Typically the harness will have several unplugged wires for analog gauges, so don't be alarmed by that. Assuming that you have digital gauges, see the attached document. It is for a dual engine set up, but easy to figure out for a single engine. View attachment Electrical Diagram Honda Digital Gauges Dual engines.pdf

Pull the fault codes and let us know what you get. If the MIL light stays on, there are no codes.

Well... Found out several things today. One, the harness connected to my controls is the wrong one and the MIL and Batt lights are not connected. Spoke with Don, the mechanic at the Boat shop in Fairbanks. He listened to my issues and immediately gave me instructions to check the
Well... Found out several things today. One, theharness connected to my controls is the wrong one and the MIL and Batt lightsare not connected. Spoke with Don, the mechanic at the Boat shop in Fairbanks.He listened to my issues and immediately gave me instructions to checkthe thrust washer. He stated the cam shaft gets worn and causes the oil pressure failure warning as the tolerance is too great.

Pulled the air intake and found the pulley moved .050", well out of the tolerance of .018". S there it is. Any words of wisdom... Don told me that he is going to check in the morning and see if there is any chance of a warranty fix. This is the most common failure I have read about for the Honda motors and can't believe that Honda has not done any kind of recall to solve the problem. After reading about this problem over and over, I will definitely not be buying honda's for my new repower.

BTW, I want to place a shout out to Don at the Boatshop in Fairbanks. He was over his head with work to do and took the time to help me out. He was spot on with his knowledge and I would go to him for any repairs that I had to do on a Honda. I know most of you are not in Alaska, but wanted to make it known.