1998 merc 225 efi alarm/continuous/devil/possessed

[redduke]

a 2 year mystery,turn the key on sometimes and i get a continuous alarm,the motor hits once,but will not start.Next time get the go ahead whistle and she fires up runs great.it has never died after starting.Have looked at numerous sensors,connections,appears to be pumping water fine.It comes and goes,crazy!!The only clue is when the continuous alarm is going off the tach needle bumps up slightly.Any thoughts before i loose my mind...Oh yea its been boat dealer twice,shade tree boat tech twice,with no real promise

 

[redduke]

Also, this alarm does not go off every time,maybe turn the key on and off numerous times in the course of couple weeks before it acts up

 

[mechanicman]

The alarm module may be bad.