Greetings Thrillseekers:
I have a 2003 Honda BF200hp engine (on a Triton SF21) that has been acting up for the last couple of seasons. The blame has always been that the most recent Oxygen Sensor (O2 sensor) has failed but I suspect something more as replacing the O2 sensors hae not eliminated the problem. Here is what I am experiencing:
Engine alarm (beeping in three second intervals) goes on when engine has been idling for a short time (usually after about three minutes). Engine alarm (beeping in three second intervals) goes on when engine is moving slowly in gear (usually after about three minutes).
Engine will sometimes have a low idle and shut itself off as I shift from forward idle to neutral.

Also, on an irregular basis, engine alarm (sold tone) goes on when at planning speed. If acceleration is not dramatically reduced, engine will automatically reduce power and shortly thereafter turn itself off. Typically, alarm will continue to sound and I will reduce throttle to almost idle speed. Alarm then usually shuts off.

In all the above situations, alarm sounds cease once engine is turned off and restarted.
In all cases, engine looks to be properly discharging water.
In all cases, no lights by throttle or by key illuminate.

My Honda mechanic who I trust, has replaced Oxygen Sensor several times. FYI: I do not experience rough idling on an ongoing basis which I have been told is an indicator of a faulty O2 Sensor. Engine may start and run rough for a brief period but always adjusts itself.
I have replaced the engine battery in the last four months.

I am tired of this ongoing issue and hope that someone has a suggestion that my mechanic can check.
Thank you.