OUTLAW EAGLE MANUFACTURING

[Alumaman]

2009 KEM 8.1 HO with a whistling sound coming from the throttle body. Only evident between 2700 and 2800 rpm?
I have read that this is a VERY common issue with the glass boat big blocks.
Also found that Mercury uses an "IAC muffler".
I spoke with KEM and they have never heard of it.
Part #5 in the below link to a merc drawing. It looks like a mini air filter inside the throttle body, over the IAC port.

I'm wondering if this Mercury fix could apply to a Kodiak? Or, maybe an after market air filter in place of the steel mesh flame arester will help muffle it.

Any help or comments appreciated.

http://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=881784002&ivar=images/COMMON/6776.png&inbr=11415&bnbr=70&bdesc=Throttle+Body%2C+Mechanical+Throttle%2DShift

[Boomhower]

Hey Rich, How bad of a whistle is it? Your boating pal has mentioned that his 6L. has a bad whistle around 2700-3000. I have noticed on almost all of the engines that I have tested in boats that have a forward facing intake such as the 496, 6L, LS3 have a whistle. Some worse than others.
The LSA obvoiusly does because of its supercharger. I cant explain it but I will asure you its normal. There is cone shaped low profile K&N filters avilable to fit the neck of the throttle body to replace the wire mesh spark arrestor, It may help...

[jack]

Hey All ,
I'm not going to say it's not the IAC porting but that's an idle control circuit so at 27-2800 rpm ?
Check this out http://www.2carpros.com/how_does_it_work/how_an_idle_air_control_iac_works.htm
jack

[DOC]

Hey richard i put a k+n filter on my 8.1 in my pickup and it whistles too. Just turn the tunes up.

[Alumaman]

Jack, I know waht you mean. It should not be related. But from what I had read its the air flowing in the throat of the intake passing across the opening of the IAC port. Creating a whislte. I think I will get one of those 3$ Mercruiser peices of foam and try it.

Dave, thats not your 8.1 whistling, its thats girl you picked up hitch hiking.