ecu going bad 2002 f 115

[dnrlabs]

I own a 2002 23' reg with twin F115 . I had a issue with my iac not firing up no clicking sound . Had mobile mech come to trouble shoot found defective ecu swaped starboard ecu to port side iac functions boat starts. So gave him go ahead in buying brandnew ecu. Replaced and hooked to computer all okay .Took boat out ran for 30 min and sure enough starboard would not start got back to dock called mech said looks like the starboard ecu had failed as well no iac sound. Sure enough took to another mech and they said that it was in fact another bad ecu. Checked grounds hooked up computer checked wiring . Hooked up computer diagnostic 2 ecu one with o hrs the other 0 hrs. 2 brand new ecu's ran boat for three days boat stalled and sure enough port side ecu failed 7 hrs total.Can some one help me . Something is blowing my ecus 2 seperate motors each with bad ecu's. Each has independent batteries and cables. Called Yamaha and they are clueless

[99yam40]

You might do some searching on the forum about IAC sticking and over heating, I believe if too much current is pulled it will burn out ECU.
Not sure it that was for a F115 or maybe it was F150
Here is a thread on a F115 that has a lots of info from Rodbolt(Yamaha master tech)
ISC is what they talk about damaging ECU, so do not know if that is the same as IAC
Look at post #48
http://www.yamahaoutboardparts.com/f...e-th15590.html