2011 BF 225 fuel issues?

Hello All,

I have a 2011 BF 225 that I have done some significant work to but continue to have issues with a DTC 1 alarm.

Items I have addressed in last 12 months:

1. HP and LP fuel pumps with replacement of all screens/filters
2. O2 sensor
3. Fuel lines and filters
4. Port side power head with all major gaskets and valve adjustments per honda manual
5. Complete VST re-build
7. Spark plugs
8. Vertical shaft bushing

Boat ran well after replacing the port side power head last summer. No alarms. Expected performance. Recently been taking the boat out and getting the DTC 1 alarm going off. I would turn the motor off and re-crank then be good the rest of the day. The alarm became more frequent and now will not go away.

In the last few days I have checked my spark plugs for issues and seen no signs of water intrusion. Tested the O2 sensor with multimeter and all numbers appear appropriate. 7.5-8.5 omhs (within range based on honda manual) and voltage response appropriate to heat application. Taken out the injectors and cleaned. Seem to have equal spray with no obvious issues. No water in fuel.

Only thing that seems out of norm is when I tested the fuel pressure. With the motor idling around 650rpm the fuel pressure is 38psi. I read in the manual it should be between 41-48psi. Is this a big enough difference to cause the alarm and make the engine idle somewhat rough? Honda manual says the fuel pressure regulator could be the issue. Anyone had issues with them in the past?

I feel like I've had nothing but issues with this motor since taking ownership. Any advise is appreciated. If I can't figure this out then I will be taking it to the shop for them to put the computer on and see if there is something else going on vs just replacing the fuel pressure regulator and new 02 sensor.

You have a failed O2 sensor again. What is the serial number, I have a feeling this engine should have had an ECU and sensor change? Your fuel pressure should be around 40psi at idle with the vacuum hose connected and should increase to 48 with vacuum disconnected or at high revs.Another thing I have come across is water getting onto the O2 sensor by a leaking bottom manifold seal, the rubber seal that sits in the mount case exhaust pipe, if this is damaged or incorrectly installed you will have the same issues as a failed O2 sensor.

iang6766 said:

You have a failed O2 sensor again. What is the serial number, I have a feeling this engine should have had an ECU and sensor change? Your fuel pressure should be around 40psi at idle with the vacuum hose connected and should increase to 48 with vacuum disconnected or at high revs.Another thing I have come across is water getting onto the O2 sensor by a leaking bottom manifold seal, the rubber seal that sits in the mount case exhaust pipe, if this is damaged or incorrectly installed you will have the same issues as a failed O2 sensor.

Click to expand...

Thanks for the reply iang6766. Serial number is BAGJ-1601907. I'm not sure if the ECU has ever been replaced. I bought the boat/motor in 2018. I feel like it is the O2 sensor. I will look into the bottom manifold seal and rule that in/out. Can you describe the bottom manifold seal better so I/m sure that I am looking at the right thing? Thanks. This forum has always been helpful in trouble shooting.

All you need to do is idle the engine for a couple of minutes and then pull the O2 sensor out and check there is no moisture on it.

Okay, I just did that yesterday. O2 sensor still warm when I pulled it and no moisture. Will do it again today or tomorrow to be sure. Will likely order a new sensor and reset the codes. Maybe I got a bad sensor..... fingers crossed. Thanks for the quick replies and advise.

So, think I have finally got her back working.

Replaced the 02 sensor, fuel pressure regulator, and HP fuel line running from the HP pump to fuel rail. Cranked the motor and no more sensor but had an obvious miss fire in one cylinder. Found it to be the #4 cylinder. Replaced the sparkplug in #4 and check to be sure the coil was firing. Good coil fire and good sparkplug but still no fire in that cylinder. Recently pulled all injectors and cleaned. Had a suspicion that the injector was not providing fuel and moved the injector into the # 2 cylinder and the miss fire followed the injector. Replaced that injector and now the engine is running well without any alrams. Good fuel pressure. Thanks for the advice lang6766. Will take it for a test run this weekend.