Guys with IAC issues tell me what you think

[jiriki 13]

I threw mine away... there was no hope in saving it.

[Bigcatpt 408]

So I cleaned up my flame arrester and IAC filter using some carb cleaner. it really cleaned them up pretty good and the little filter did not fall apart. I put everything back together. I was hoping to get on the lake today but that did not happen. So i hooked the boat up to a fake a lake and started it several times on the driveway. It started up good everytime I turned the key. So hopefully that has solved my hard starting issues. I will get it out on the water this week to really give it a good test and let you know.

[jiriki 13]

Good luck! Keep us informed.

[Babylon 23]

My boat has the same symptoms as mentioned in this thread. I have the 6.2 Black Scorpion motor in my Enzo 240. How do I access the IAC filter? I think I can find it between under the Black-Scorpion plenum but between that and the port manifold riser, I can't access the thing.

[jiriki 13]

It's easier to take the plenum off. Once it's off, it's right there in front of you.

[Bigcatpt 408]

So I wanted to follow up on this IAC muffler thing.

 

So I pulled mine out, and because nobody had one locally on short notice I cleaned it really good with carb cleaner and re-installed it. I cleaned up the flame arrester as well which was really dirty.

 

I started it on the driveway it started great each time and ran great.

 

I then took the boat to Lake Powell. My wife and son drove my boat while I drove the houseboat. So they ran the boat for several hours before I ever got in it. The first time I started it I heard a noise that I had never heard. It was like the engine had sprung an air leak. It was like a hissing sound. I popped off the flame arrester and looked into the manifold. The IAC filter that I had cleaned was GONE. It must of got sucked down into the motor....Poof! The loud hissing sound was coming from where the IAC muffler goes. Maybe that is why it is called a "muffler" and not a filter. I did a little reading and the boat will run just fine without the muffler in there....and it indeed did run great....but quite noisy. We used the boat all week like that without issue. And it totally fixed my intermittent hard starting problem. When I got home the IAC muffler that I ordered from the local boat part store had arrived. I Installed it this week and we hit the lake yesterday. The boat ran like a champ. No more starting issues. And the muffler took away the loud hissing sound.

 

The IAC muffler is a cheap fix (less than $2). I am going to make it a habit to change it out ever couple years as well as cleaning out my flame arrester.

 

Here are a couple pics.

This is the dirty filter I pulled out of the manifold. The flashlight and nut are for size reference. It looks like a dirty cotton ball but is a stiffer material.

 

This is the packaging for the new IAC muffler (package on right size) Part # 35-863829

 

This is the new muffler. It has much more material than the one that I pulled out did. It was a much tighter fit putting it in the little slot that it goes in.

 

Anyway I hope that this may help someone in the future with similar starting issues.

 

[Bigcatpt 408]

Just linking a few other related posts for future reference....

http://www.centurioncrew.com/index.php/topic/9348-boat-dies-when-returning-to-idle-please-help/?hl=%2Biac+%2Bmuffler#entry118310

http://www.centurioncrew.com/index.php/topic/9109-issues-starting-after-it-has-ran-for-awhile/page-2?hl=+iac%20+muffler

http://www.centurioncrew.com/index.php/topic/9310-iac-valve-help/?hl=%2Biac+%2Bmuffler#entry117516

[jiriki 13]

Where did you order yours? I don't think I saw them for less than $2 but for that low.. I'll replace it.

[Bigcatpt 408]

Any Mercruiser dealer should be able to order them for you.

 

A quick online search shows many sources for the IAC muffler

 

http://www.lowcostboatingstore.com/QUICKSILVER-35-863829-INTAKE-AIR-CONTROL-MUFFLER_p_26941.html

[RhuntIII 555]

Dang it, I wish I would have frond this thread earlier. Thanks Bigcatpt for the heads up. So after the crew weekend I having the same problems as the beginning of the thread. That is what spawned the Yearly Maintenance thread. I going to tackle this repair I have an IAC valve on order and now a IAC muffler on order. I hoping with these repairs She'll be up and running. Once I get the parts I'll take pics and post up on here. I'm running the same motor as Bigcatpt. Merc. 350 MAG.

[RhuntIII 555]

I.A.C. this is the idle Air Control valve and sensor on a 2002 Merc 350 Mag. The double beep and the computer led me to replace this. The black plunger will not move on the old one like it will on the new one.

[RhuntIII 555]

Three more

[Bigcatpt 408]

So did this fix your beeping problem? Did u replace the IAC muffler/filter as well? I forgot to tell u to get a gasket for the IAC when you ordered it. I forgot to get one for mine as well. But nice job making one! I hope this fixes your issue. Looks like you sanded your water pump backing plate too. Looking good.

[RhuntIII 555]

That's as far as I got today. Big you mentioned somthing about a gasket for the distributor cap? I couldn't find one. A new muffler is also on the way.

[truekaotik 458]

It should come with the cap Rhunt...

[RhuntIII 555]

No it did not. This will be the second one I've installed, no gasket.

[duramat 462]

Rhunt, what brand are you using? (Cap)

[RhuntIII 555]

It's either Merc or Quicksilver. I couldn't even find it in the part lists.

[CeeDee 16]

Can someone post a pic of where this IAC muffler is located on the MAG MPI motor ?

[RhuntIII 555]

I can but it will have to be after this weekend. There is a what looks like a 1/2" hose that comes out of the bottom of the throttle body that goes to what you see in my earlier photos. Then another 1/2" hose runs from the AIC to.. I'm guessing the intake manafold. Since the engine is in backwards then the AIC is at the back of the throttle body, top of the engine headed towards the bow of the boat. I'll take more photos when I get back to wrenching.