350 MAG MPI - Stalls when going to idle

[ss3964spd]

So after 8 years of trouble free operation we've had our first issue with our boat.

Heading back to the ramp after a beautiful day on the water. Everything running normally, we enter the narrow channel at about 30 MPH and started gradually slowing for our approach to pass under the bridge. No out bound traffic to worry about, water calm, no wind, no current.

We're lined up nicely, and maybe 40 yards from the bridge, so I pull the throttle back to idle speed. Alarm sounds, engine dead. Crap. Key off, throttle lever to neutral, turn key. Engine cranks just fine and sounds like it maaybeee wants to start but doesn't. Crap. Push throttle lever center button to disengage out drive shifter, and open up the throttle a bit, cranks, starts, and sounds fine at about 1000 RPM's.

Temp, oil pressure, volts are all normal. Return throttle to neutral to re engage drive shifter, alarm sounds and engine dies. Will not restart in neutral. I have one crew member grab the pole hook to fend off if necessary but our previous momentum and heading carries us under the bridge safely. Once on the other side, same story; can restart with throttle advanced but as soon as it's returned to neutral it stalls. I finally was quick enough with the throttle lever to get it in gear but can't run it at idle speed so we're heading to the ramp dock a little hot. Throttle back to idle speed maybe 30 yards from the dock and it stalls again. Our alignment was great so drifted right to the side of the dock and I was able to grab a cleated and hanging dock line and bring her to a stop. Once tied up I test again, same symptoms.

Ideas? My first thought is the Idle Air Controller (IAC).....

[mmwjr]

Dan where the heck you been buddy?

Becky doing well?

I agree sounds like the IAC.

[ss3964spd]

Doing great, Mike, busy as all get out though. Becky's doing great also, changed jobs not too long. Enjoying the new gig but has been putting in a LOT of hours and travel. Can't find too much sympathy for her though, since she's recently been to Vegas, Miami, and is headed to Paris in 10 days, all for work. Sure, "work".

How are you and your fam doing?

I started my day yesterday glowing with the good fortune of being the designated captain to 5 lovely's aboard the boat for the day, and my good fortune prevailed right until I had to get that boat stopped at the dock! None of those wimmins were about to grab any part of that dock. LOL

Yeah, I'm hoping it's the IAC, seems logical. To be honest though I don't recall if I ever got an alarm while the engine was still actually running. I know the alarm will sound for temp, oil pressure, low volts, and low outdrive lube level, do you know if the alarm will sound for any other reason?

[mmwjr]

Glad to hear you and Becky are doing well.

My girls are doing well but been working on a divorce for well over a year now. All in all I am doing ok just want to wrap up that chapter of my life and figure out the rest of my life.

I am thinking the alarm sounds due to low OP and volts as the engine is about to die as the rpms drop off. Did you notice the rpm when the alarm sounds?

[ss3964spd]

Agreed, Mike, about the alarm just as the engine stalls. I just wish I could remember if I heard a couple of beeps as I was gradually coming off plane and just before returning the throttle to idle speed. I kind of think I did but didn't think anything of it, probably dismissed it as maybe being a little low on drive lube.

I did find a post on another forum by someone who described my scenario almost to a tee. http://www.boatingwinnebago.com/foru...-every-minute/

Glad the girls are doing well, but sorry about the divorce Mike. Been there, done that, approximately zero fun. If it has to happen I hope you two are able to work closely enough together to make it as painless as possible for the girls and yourselves.

Feel free to drop me a PM if you'd like to chat.

Dan

[mmwjr]

Keep us posted on your findings.

Thanks for the offer to talk I really appreciate it.

[CaptNCamille]

Idle air control valve. Same thing happened to me after about 8 years of trouble free operation. That's what it was.

[ss3964spd]

Thanks CnC, appreciate the confirmation. I suppose I could have the marina service center scan the computer but everything I've been reading, and the symptoms, points right at the IAC. I'll replace it myself and report back.

Thanks all......

Dan

[ss3964spd]

Replaced the IAC today. Probably the easiest job I've ever done on the boat, took maybe 45 minutes. Took longer to put the boat in the water, test it, and take it out of the water.

It started right up in neutral like it should. I let it idle away up to its normal operating temp of an indicated 175. Disengaged the drive from the throttle lever and ran it at about 1100 for a couple of minutes then quickly returned it to idle. Purrrrfect.

[CaptNCamille]

Great, glad to hear all is working well. Happy boating!!

[mmwjr]

Now get out there and use it!

[ss3964spd]

Thanks again Mike and CnC.

Yes indeed, have a crew lined up for Sunday, supposed to be beautiful here.