2001 dt140 stalling and rev alarm

[kadima]

about 2 months ago a family friend "tuned" our engine and put new plugs in it. since then it will not idle, continually stalls and the rev(?) alarm goes off. Our mechanic said we needed a new ecu and we replaced at a cost of $1400+. The same problems persist and the mechanic is stumped-says rest of engine is "perfect"! Boat has been in shop for 2 months with no end in sight. Any advice on what to look for would be appreciated.

[mitch]

did he connect up to the computer sounds like you have a sensor problem

check the wiring does not have water ingress some where in the joints..