4.3 runs great dies at idle

[ACV97]

2004 280DA and first thing in the morning the motors start right up and will idle right out of the marina with no problems. Run them a little and when pulling back ti idle the port engine will die. It will start back up and with a little gas it will dies again. The boat is new to me so I am going through the gas as I do not know how old it is, I was also thinking I need to replace the fuel/water filter. What are some other ideas? IAC? Seems like once the motor colls a little it idles great. Water temp runs the same but the water psi is a little lower than stbd engine. Am alarm goes off but I believe it is the trim fault, getting fixed this week. But sometimes a beep happens and nothing reads on the gauges, is there another place I should check. Oil PSI and water temp have always been good.

 

[Thomas Molin]

I guess you have the MPI´s? In that case I am pretty sure that it is your IAC. The easiest way to find out is to switch the port and starboard IAC to see if the problem change to the other engine. I think it is just four bolts each, so it´s an easy swap.
If it turns out to be the IAC, I would change both since it is likely that the other one fails soon anyway.

 

[ACV97]

Good solution, one of those why didn't i think of that things. Still getting used to twins, I know it is really tough to dock a twin boat with only one engine.