Thank you for the help - Replaced IAC

tginz

tginz

New Member
Jan 7, 2008
148
Guilford, CT
Boat Info
2004 240 Sundancer
Engines
5.0 w/ Bravo 3
I can't thank all the folks at this forum enough. I lost idle & power in my 2004 5.0 engine - 194 hours last weekend. Limited power underway, a double beep alarm every one minute from the SmartCraft....Not a "real" problem until I reached the dock and found I had NO idle. Reaching the dock was done by starting and restarting with shots of throttle. Now that was a professional landing. Once the engine cooled, I had a No start condition.

Anyway I'm a usual here and searched 5.0 idle issues. Like with any problem this site is a bonanza of information. Previous posts listed the alarm sequences for the SmartCraft and the corresponding alert issue. No idle and one minute double alarm could only be the IAC. While local dealers did not have them in stock, I contacted JD Neeson @ marinepartexpress.com in Maine. JD told me they alone have sold 40 this year. Arrived overnight no charge (thanks JD) and my 5.0 is ready for the weekend.

Like someone commented in a previous post - If you own a 5.0 you're fool not to carry a spare IAC & a 3/16" hex wrench. OK, I'm a believer!

* The IAC (Idle Air Control Valve) is the small solenoid behind the air filter which controls the engine idle. It has two hoses on the port side which are attached to a lower air manifold, two hex screws on top of the solenoid with gasket between the upper & lower, and one electrical connection starboard side. Took all of 5 minutes to change, but do purchase a gasket when changing. Instantly I went from no cold start to running like a champ and idled just like always.

Thanks again to everyone for all the previous IAC posts. This site is wonderful resource!!!:thumbsup::thumbsup::thumbsup::thumbsup:

tginz
Tom Ginz
 
Total was about $105.00 and another $1.50 for the gasket. marinepartsexpress.com offered free shipping.
 
I also carry a spare. Funny thing-- the hours on each of my engines when the IAC went bad was 190 on one and 200 on the other....you were right in the middle. Same engine as you...I guess that's a good proxy for others.
 
Same with the 4.3's. Mine went at 180hrs on starboard and 190 on port. I now carry a spare and 3/16th hex. I'm actually going to buy another spare so I have 2 onboard.
 
My jackknife style Allen wrench kit did not have the correct size. I had to pull out my big, loose piece kit. Just suggesting you check ahead of time.
 
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If you have an IAC muffler in your throttle body (looks like a small 1/2" sponge) order some of those as well.
 
TurtleTone said:
If you have an IAC muffler in your throttle body (looks like a small 1/2" sponge) order some of those as well.
Click to expand...

:thumbsup: Highly agree here.

Just put a spare IAC, gasket and muffler on my boat this weekend. Also... couple spare relays. My fuel relay seems to be frying on me lately. :smt013
 
Howdy everyone -

First post here. I've got a 2005 185 sport with a 4.3MPI that quit idling this weekend. I am fairly confident that it is the IAC valve, as I have replaces several of these on cars and trucks.

Anyone know of the automotive equivalent to the Mercruiser part? Autozone is a lot closer than my dealer, and I'm betting it will be a lot cheaper as well.
 
TexasA&M said:
Howdy everyone -

First post here. I've got a 2005 185 sport with a 4.3MPI that quit idling this weekend. I am fairly confident that it is the IAC valve, as I have replaces several of these on cars and trucks.

Anyone know of the automotive equivalent to the Mercruiser part? Autozone is a lot closer than my dealer, and I'm betting it will be a lot cheaper as well.
Click to expand...

Welcome to the board, I am not sure about the non merc equivalent but if you don't mind waiting for shipping you can try this site

http://www.mercurypartsexpress.com/us/

I just picked one up for $109 i believe.
 
I've heard here and from my local Marine Max mechanic that they fail often, so I guess I'll be putting a spare in my toolbox since my engine has 140 hours on it.

Does anyone know what the failure mode is? Is the solenoid coil going open -circuit and/or shorting to ground? Or is it that the mechanical valve/seat is leaking or stuck open or just getting plugged with crud? I'm considering pulling mine out now and inspecting it electrically and mechanically for signs of weakness.

Building a solenoid valve to last more than 200 hours and tens of thousands of cycles should not be a challenge these days, even for a marine engine application. I wonder if Merc has a fix in the pipeline yet?
 
Where exactly is this sucker on a 4.3MPI? I know it's somewhere right on top of the intake manifold, but I haven't started looking for it yet. Any tips so that I can find it easily?
 
Here's a shot of one on a Mercruiser 350 MAG MPI:



It takes a 3/16" hex wrench to remove the two screws. There is a gasket under the valve also.
 
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Perfect!! That's exactly what I thought it was, but it doesn't look the same as all the replacement parts I've seen. I'm going to pull it off today and take it to the parts house and see if I can find a matching automotive part.

Also, what/where is the foam muffler everyone is talking about? Are those only one some designs, but not others?
 
I just replaced the IAC on my starboard engine. The hardest part was getting through the many layers of black paint. On my 5.0L MPI's, the little muffler was down in the throttle body on the side nearest the IAC valve you are replacing. It was just stuck down inside, and kind of hard to see. I didn't take any pics. There are several thread on this repair. Don, thanks for the pic....I recall seeing it posted in another thread and greatly aided in doing this repair.
 
TexasA&M said:
Perfect!! That's exactly what I thought it was, but it doesn't look the same as all the replacement parts I've seen. I'm going to pull it off today and take it to the parts house and see if I can find a matching automotive part.

Also, what/where is the foam muffler everyone is talking about? Are those only one some designs, but not others?
Click to expand...

Here it is... the reason for the IAC (Idle Air Control) Valve is to allow a small metered amount of air to bypass the butterfly valve when it is closed (engine idle) as seen in the picture. If the valve piston freezes closed, no air can get to the intake manifold and your engine won't start or will not idle. The fuzzy brown thing is the muffler and I believe only filters the air coming from the IAC Valve.

See Turtle Tones post #9 here also: http://clubsearay.com/forum/showthread.php?t=23361&highlight=IAC+valve



http://my.jetscreenshot.com/81/20090916-837d-146kb
 
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damn, you need to change that muffler, it's dirty.
 
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