Honda Outboard waterpump indicator flow not working

[SAUERKRAUT]

50 Hp Honda outboard about 10 years old, reliable, and runs perfectly. Saltwater. The indicator water pump discharge has not worked for about 5 years, despite attention by my Honda dealer, and my own efforts at salt and calcium dissolving flushes, probing and air compressing the discharge vent. The water pump is meticulously serviced. Never any engine overheat problems or issues.

My Honda dealer insists that this situation is common with older engines as the tiny channels in the engine block do eventually become calcified, clogged, and otherwise not accessible for salvage. Certainly, said dealer has been correct for 5 years however, this still bothers me. Furthermore, said dealer states that if an over heat situation arises, the appropriate over heat alarm will sound "so I am safe".

I mentioned the above to a friend of mine who also runs Hondas. And he says "bull#^&#^&#^&#^&". He is an experienced, hands on engine mechanic who services all his own equipment for his large landscaping business, as well as his boats.

Does anybody have any experience about this waterpump indicator issue for a Honda outboard?