High Pitch intake whistle GONE!

[02-Scape]

The intake on my boat had a loud whistle that was really irritating at certain rpms (2600 - 3200) right at the speed I like to cruise at. Boat was still under warranty so I went back to the dealer who went back to Indmar. Dealer and Indmar came back with 'we will talk to you about it a bit but because we already have your money, we really will do FA about it. Besides that ear piercing screech is "normal" so FU very much for asking'

Was zooming around on the Natique forms, seems like some of their boats had the same issue. Instead of abandoning there customers, PMC actually did something and came up with the attached.

Of course they would not sell me one so I built a crude one using a jigsaw - see second attachment. It bolts on right in front of the throttle body.

The whistle is completely gone the boat performs exactly as it did before

Looks like my phone photo is too big too attach, will resize and repost but you will get the jist by looking at the first photo.

It's a quick cheap fix for a big problem (I was ready to unload the boat)

Just thought I would share

[BlackBluMalibu]

Great job!

[Fman]

I had the same issue with my 2011, they ended up replacing the intake manifold and it took care of it. That is a great fix there, you should send it to Indmar so they can see what to do. Our was also ear piercing at same rpm range when sitting in back seat area, glad you got rid of it.... Nice work!

[02-Scape]

I had the same issue with my 2011, they ended up replacing the intake manifold and it took care of it. That is a great fix there, you should send it to Indmar so they can see what to do. Our was also ear piercing at same rpm range when sitting in back seat area, glad you got rid of it.... Nice work!

I actually sent this to Indmar but no response. It's actually quite easy to fabricate, I got a gasket from malibu and traced it on to sheet metal used a drill to make the bumps and cut the rest with a jig saw, mine is way more crude than the PMC one but it still works. You just need to create a small hump to make the airflow a bit turbulent, the bumps barely extend into the air stream because the butterfly valve will hit them if they are too tall.

[atomicrider13]

Do you remember what gasket / part number this was?

[02-Scape]

Do you remember what gasket / part number this was?

No but it's the gasket between the throttle body and the air intake

[atomicrider13]

Scape,

I was able to get my hands on one of these gaskets! (I will trace it and get all the specs before installing for anyone else having the problem) Just to be clear on installation, this goes before the actual throttle body in between that and the air cleaner not between the throttle body and the intake plenum? Did you happen to take any pics of your install?

Thanks!

[justgary]

Any chance you can scan it and post an image?

[02-Scape]

Scape,

I was able to get my hands on one of these gaskets! (I will trace it and get all the specs before installing for anyone else having the problem) Just to be clear on installation, this goes before the actual throttle body in between that and the air cleaner not between the throttle body and the intake plenum? Did you happen to take any pics of your install?

Thanks!

Nope between the throttle body and the intake plenum.

[minnmarker]

Scape,

I was able to get my hands on one of these gaskets! (I will trace it and get all the specs before installing for anyone else having the problem) Just to be clear on installation, this goes before the actual throttle body in between that and the air cleaner not between the throttle body and the intake plenum? Did you happen to take any pics of your install?

Thanks!

Update? Part number? Pictures? Results?

[Chia]

not sure how i missed this in 2014, but what does this gasket thing look like and how will it stop the whistling (actually i don't care how, just that it will)....oh, and where can i get one??

[ryguy1188]

Scape,

I was able to get my hands on one of these gaskets! (I will trace it and get all the specs before installing for anyone else having the problem) Just to be clear on installation, this goes before the actual throttle body in between that and the air cleaner not between the throttle body and the intake plenum? Did you happen to take any pics of your install?

Thanks!

Were you able to make and install the spacer? I have this same issue so I am thinking about doing this fix but I have a few questions.

Do you have to add a new gasket when installing the spacer? So it goes, Intake plenum, gasket, metal spacer, gasket, throttle body?

[atomicrider13]

The gasket they sent didn't fit... back to square one

[ryguy1188]

So I was able to speak with both PCM and Indmar and PCM said they found their solution through Volvo. (Gasket # VDP 3849022). They said you can find this PN through any Volvo dealer. I asked Indmar if they have heard of PCM's solution, and they said it won't work (their assumption) because the whistle is from the butterfly valve. So Indmar recommends to take the sharp burr of the butterfly valve as a fix. Indmar also went to say that the PCM plate won't work because the whistle is happening before the deflection gasket fix.

However with what 02-Scape said, that makes me think otherwise.

If anyone is able to order the part number PCM sent, let me know if it works out.

 

EDIT: Turns out that Gasket PN is wrong for the AR335 in my 2011 Axis. dang

Edited June 9, 2016 by ryguy1188
update

[Chia]

What's a butterfly valve and why does it have a shar burr in the first place?

[Fman]

So I was able to speak with both PCM and Indmar and PCM said they found their solution through Volvo. (Gasket # VDP 3849022). They said you can find this PN through any Volvo dealer. I asked Indmar if they have heard of PCM's solution, and they said it won't work (their assumption) because the whistle is from the butterfly valve. So Indmar recommends to take the sharp burr of the butterfly valve as a fix. Indmar also went to say that the PCM plate won't work because the whistle is happening before the deflection gasket fix.

However with what 02-Scape said, that makes me think otherwise.

If anyone is able to order the part number PCM sent, let me know if it works out.

Be careful removing this sharp burr, my dealer tried it and I had a major idling problem after this. It would not go below 900 rpms. They ended up just installing a new manifold off another boat which took care of the problem. Not sure if it was error by tech but just use caution when you start filing anything.

[ryguy1188]

What's a butterfly valve and why does it have a shar burr in the first place?

It's the metal flap that is just past the air filter in the throttle body that controls how much air goes into the engine. When they stamp out the metal, it leaves sharp edges on it which acts likes a whistle making the noise.

Fman, I can see how that can cause an issue.

[Lance B. Johnson]

Be careful removing this sharp burr, my dealer tried it and I had a major idling problem after this. It would not go below 900 rpms. They ended up just installing a new manifold off another boat which took care of the problem. Not sure if it was error by tech but just use caution when you start filing anything.

lol I was JUST going to type something like, "errrr, I wouldn't be filing on the throttle plate no matter what indmar says."

OP- Great fix! If I had the issue I would be right on your heals making a special......diffuser? is that what the technical name would be?

Edited December 10, 2015 by Lance B. Johnson

[Steve B.]

Great job. That whistling has been annoying a ton of people for a long time.

Steve B.

[02-Scape]

So I was able to speak with both PCM and Indmar and PCM said they found their solution through Volvo. (Gasket # VDP 3849022). They said you can find this PN through any Volvo dealer. I asked Indmar if they have heard of PCM's solution, and they said it won't work (their assumption) because the whistle is from the butterfly valve. So Indmar recommends to take the sharp burr of the butterfly valve as a fix. Indmar also went to say that the PCM plate won't work because the whistle is happening before the deflection gasket fix.

However with what 02-Scape said, that makes me think otherwise.

If anyone is able to order the part number PCM sent, let me know if it works out.

Pretty sure mine was coming from where the manifold meets the block (as far as I could tell). It seems that disrupting the airflow just a little bit is enough to silence the whistle. I did file the butterfly valve a little but it did nothing. The spacer cured the problem no whistle at any RPM.

[Chia]

Pretty sure mine was coming from where the manifold meets the block (as far as I could tell). It seems that disrupting the airflow just a little bit is enough to silence the whistle. I did file the butterfly valve a little but it did nothing. The spacer cured the problem no whistle at any RPM.

by spacer, are you referring to the volvo gasket?

[02-Scape]

by spacer, are you referring to the volvo gasket?

No the plate I cut out and put between the intake and the throttle body (I don't have a picture of it and my boat is 3 hours away), it looks roughly like the picture in my first post, mine has only 3 bumps per side. If you pull your throttle body off you can use the foam gasket to make a pattern for it, the bumps only stick out into the airflow about 1/2 cm. I used sheet metal and a jigsaw to cut it out.

[Chia]

No the plate I cut out and put between the intake and the throttle body (I don't have a picture of it and my boat is 3 hours away), it looks roughly like the picture in my first post, mine has only 3 bumps per side. If you pull your throttle body off you can use the foam gasket to make a pattern for it, the bumps only stick out into the airflow about 1/2 cm. I used sheet metal and a jigsaw to cut it out.

please excuse my ignorance, what foam gasket?

[02-Scape]

please excuse my ignorance, what foam gasket?

The throttle body is the part that the air filter is attached to, which is bolted to the intake plenum (not trying to be ignorant but just to be clear). If you unbolt the throttle body (4 bolts), you will see that there is a foam gasket that is between it and the intake plenum. If you are careful you can just peal it off (and reuse). Once you have it off you can use it to make a pattern on some sheet metal (I used some that was about twice as thick as tin). This should mimic somewhat the picture I posted in the original post. Once you have done that, then take the newly made spacer and the foam gasket and put them between the throttle body and the intake plenum, bolt it back together, bolt the intake back on and you are in business. Just make sure the 'humps' you make on your spacer are small enough that the butterfly valve on the throttle body does not hit them. Hope this makes sense.

[02-Scape]

The throttle body is the part that the air filter is attached to, which is bolted to the intake plenum (not trying to be ignorant but just to be clear). If you unbolt the throttle body (4 bolts), you will see that there is a foam gasket that is between it and the intake plenum. If you are careful you can just peal it off (and reuse). Once you have it off you can use it to make a pattern on some sheet metal (I used some that was about twice as thick as tin). This should mimic somewhat the picture I posted in the original post. Once you have done that, then take the newly made spacer and the foam gasket and put them between the throttle body and the intake plenum, bolt it back together, bolt the intake back on and you are in business. Just make sure the 'humps' you make on your spacer are small enough that the butterfly valve on the throttle body does not hit them. Hope this makes sense.

I found a couple of old pictures that might help you out but I don't know how to post them, will try and figure it out later today.