My BF250 isn't sitting low in water, instead it is sitting high on water : motor is mounted raised up to penultimate hole. More over on my boat it is possible to mount two engines with 200 hp, so a single BF 250 isn't a heavy weight.
What percentage of faults in BF 250's O2? I do not know. I think an outboard mounted on a pontoon is less prone to O2's breakdowns, so the pontoons lower the percentage.
I am sure that my engine mounted on the trestles with cup flusher, on the ground, in 100,000 hours of operation would have no problem with o2 sensors.
Obviously the outboards are bought to work in the water, and Honda should design and build them to work in the water.
On the percentage of faults in BF 250's O2 I can say what I saw. Where i live the bf 250 are few, in the marina where I moor my boat there is only mine.
Nevertheless over time I have seen two bf 250 pass near me at very low speed with the intermittent beep that I know very well. Two events in a few elements is a non-negligible percentage.
The dealer intervened 4 times under warranty and under supervision of Honda Italy, and replaced the O2 four times. I think he did everything he could do, because what happens to me, to Topfish, to v70cat, means that there is a design error that no dealer can solve.
The problem can be solved by Honda or by the oxygen sensor 35655-ZY3-C01 manufacturer (probably ngk). Until honda does not solve the problem, in the world there will be a number of BF 250-225-200 buyers forced to pay periodically an O2 Honda tax.
I think these people have the right to buy the O2 without profit for honda, applying the same price as the manufacturer of the sensor.
I wrote to honda Italy and to
https://crrs.secure.force.com/service/marinew2c, which created the case - 09747746.
I have not received an answer to everything today , so I continue to search in the web