Unkown Whistle

[SpiderMan]

I have a new (to me) 97SN. I have noticed a high pitched whistle from around 2000-3500RPM while in forward motion. I do not believe it from the engine (GT40) as it does not make the sounds at similar RPMs out of gear. I have a hunch it may be the prop, which is a 4-blade OJ Legend, but I have not been able to completely lock it down. The prop does not have dings on it. If anyone would be able to shed some light on this that would be fantastic. The sound isn't deafening, but to me it is annoying, especially in an otherwise superb boat, and if I knew a way to get rid of it I probably would. Thanks!

[DanielC]

RE: Unkown Whistle

My 1997 ski has a whistle just off idle, sometimes. I think it is from the transmission. Being just off idle, I just ignore it. My Ski, has 1800 hours on it. My barefoot boom has a hole on the bottom that whistles at speed, also.

[SpiderMan]

RE: Unkown Whistle

I would say it is some harmonic sound, over any transmission sound, and only when I am on plane.

[DanielC]

RE: Unkown Whistle

Just a guess, check your fins, engine water pickup, prop shaft, leading and trailing edge of the strut, the leading and trailing edge of the rudder, and the wetted surface of the hull

[nms1991]

RE: Unkown Whistle

Try swapping out your prop with the same size pro and try it, Noises are one ofthe hardest things to track down in a boat. Also the noise could be comming from your trans as the rear gears are straight cut and they have been known to howl or whistle at certain speeds. But try the prop first and then do a shaft alignment and look at the under waterger like the strut, shaft, and rudder.

[WakeUp]

RE: Unkown Whistle

I bet it is your flame arrestor. The sound you hear is air flowing through the fins of the arrestor. It only occurs underway and under load. Try removing it just for a test. You can remedy this phenomenon by installing a K&N or competitors competition filter.

[todicus]

RE: Unkown Whistle

If you have the powerplus 1.23:1 transmission, they tend to make a whining noise at certain rpm's. I''ve been told it it normal and to just get use to it. There has been some other discussions about a fix from borg warner for that issue, but don't know the details of it.

[TRBenj]

Re: RE: Unkown Whistle

If you have the powerplus 1.23:1 transmission, they tend to make a whining noise at certain rpm's. I''ve been told it it normal and to just get use to it. There has been some other discussions about a fix from borg warner for that issue, but don't know the details of it.

The 1.23:1 power plus tranny is a PCM design, not borg-warner. The very early trannies ('89-90) did make some noise, but there was a fix available. The previous owner performed the fix on my boat- do a search here and he (M3fan) discussed it. I dont believe the later versions of this transmission suffered from the problem.

[SpiderMan]

RE: Re: RE: Unkown Whistle

Thanks everyone for replying! I will give all these things a try, though some of it may have to wait until next year seeing as how the season is rapidly dwindling here in SW MI.

[todicus]

RE: Re: RE: Unkown Whistle

TRBenj,

This is what you wrote on CCF when I asked the same question about my 95 SNOB..........

"The whine you hear is the transmission. All 1.23:1 boats make that sound- youre right its very distinct. Nothing wrong with it though."

__________________
1990 Ski Nautique
CT/MA

So now you have me concerned that my 95 should not make that "whining noise".

Todicus

[kylake33]

SpiderMan,

Did you find the source of the whistle? If so, how did you eliminate it? My 98 also has a whistle similar to yours, and I believe it is the flame arrester as well even though I have not tried to fix it yet.
Thanks.