Honda BF-50D MIL - Help Please

[Stefan-2801]

I have a Honfa BD-50D. On this one, regardless of load, speed, or throttle position, the MIL lamp comes on and goes into Limp mode (MIL on and beeps). Most of the time it happens at 3000-5000rpm, but sometimes at around 1000rpm or idling.
It feels like everything is running normally and then while driving it suddenly notices that something is wrong. After restarting the engine the MIL goes away and no more beeping. It drives normally again until it happens again. The error only occurs when the throttle position is not changed, i.e. when the throttle position remains the same. When the MIL is on it still runs normally and has power and full speed, but the moment it comes on the rpm drops minimally, about 200-300rmp (from 4300 to about 4000rmp).
I start it up fresh at Morning and can comfortably drive on the lake for 40 minutes without anything unusual.
The day later, the MIL comes on every 5 minutes or so as described and the rmp noticeably drops a little when that happens. I've already replaced the MAP sensor and temp sensor in the intake.
Please help. I suspect it's temperature dependent as it mainly only happens when the engine is warm, but I can't say for sure. I've also read out the error log by flashing the indicator with the "shunt device". I've attached a video.
Error Code

 

[Jimmy Robichaud]

The only way to really tell what is the problem is to hook it up to to the Dr. H at a Honda dealer, but it almost sounds like an oxygen sensor problem.

 

[jgmo]

I don't work on these but I have an old code chart that lists a 1 code as being an O2 problem.

There is no 11 code so I'm just assuming it's a 1 code. Like Jimmy said above, Dr. H would be the best start for diagnosis.

Here's what my chart lists for a code 1 blink...

Disconnected O2 sensor connector

Short or open circuit in O2 sensor wire

Faulty O2 sensor

Spark plug misfire

I don't even know if the code chart I have is relevant to your year model as I believe it was made for mid 2000 fuel injected outboards. So, again, Dr H would definitely provide better info if you're in a position to get it scanned.

But, it wouldn't hurt for you to maybe replace the spark plugs and do a visual check of the O2/AF sensor wiring. You might also simply unplug and reconnect the O2 sensor while the engine is OFF.

If you remove the spark plugs,
use proper torque when replacing.

Also, smear a small amount of dielectric (tune-up) grease around the inside edge of the plug wire boots/caps before reconnecting the wires. That helps seal out moisture and keeps the caps from adhering to the plug's porcelain due to heat.

Use the same dielectric grease technique on the O2 sensor wire connector to seal out moisture.

Sorry I can't provide more up to date info.

Good luck.