High Pitch Sounds Coming from Engine/V Drive

[hockz]

Wondering if anyone else has noticed a high pitch "squeal" coming from their engine and/or V Drive as you increase the speed/rpms? I notice it on my boat but it doesn't do it through the entire speed/rpm band - just trying to wonder if that is normal to hear?

[IDBoating]

You'll have to be more specific. There are all sorts of possibilities here. Slipping serpentine belt, dry shaft seal, etc. Narrow it down to where it's coming from. Even better, use your smartphone to record it and post the recording so we can hear it.

[Thegerman618]

X2 WABoating- Could also be a water pump bearings have gone out. (Just happened on mine)

[hockz]

You'll have to be more specific. There are all sorts of possibilities here. Slipping serpentine belt, dry shaft seal, etc. Narrow it down to where it's coming from. Even better, use your smartphone to record it and post the recording so we can hear it.

Okay i'll record it the next time I am out and post it. Obviously it is not a normal sound by the comments so far.

[IDBoating]

X2 WABoating- Could also be a water pump bearings have gone out. (Just happened on mine)

Another excellent possibility. There are lots. That's why we need 1) a location, and 2) a recording. Based on his comments we might be getting those.

[mdk681]

I have something similar going on. It sounds like a high pitched ringing but is only at certain lower RPMs. I'll try and get a recording as well and we can compare.


Sent from my iPhone using Tapatalk

[Thegerman618]

MDK681, Squeals are usually turning parts or moving parts. Ringing is usually metal on metal something is loose. Can you determine the side of the ringing, I may have a solution already. 99 21V guessing the Merc 350 Mag MPI? Check the clamp that holds the trans cooler in place (should be the starboard side right behind the water pump), the way that there designed when they come loose (usually gets loose when doing a water pump/impeller change) they have an awful sounding rattle, and its a stupid 1/4" nut that needs tightening, its that entire aluminum housing rattling inside a metal bracket. This is just one place to start at least.

[CRJ]

I too am a newbie but have this issue also. I recorded it this weekend but cannot figure out how to post the recording. On our 2013 z3 the squeal goes away at 3300 rpm. And shows up mostly while slowing down.


Sent from my iPhone using Tapatalk

[Thegerman618]

No update on this thread in a while, you guys ever figure this out?

[mdk681]

Finally remembered to take a video of the sound that my boat is making. As I read more I have seen a lot of posts about propeller 'singing' or 'ringing'. Any thoughts on what this noise could be caused by? It changes pitch with RPM and disappears around 1,400rpm. It sounds just like the ringing you get when you run your finger around the rim of a wine glass...

https://youtu.be/g7v7crOcEyg

A couple seasons ago I hit a rock and had some work done by the Tige dealership. Propeller was rebuilt, prop shaft and strut replaced and aligned, rudder and rudder box replaced, along with the steering cable.

[IDBoating]

Have you tried this with the transmission disengaged? As in, push the button on the throttle arm that allows you to rev the engine without turning the propshaft? I have a very slight but similar sound that is air resonating as it flows through the engine's spark arrestor. It only occurs at certain RPM's and I've heard it on other people's boats too. The RPM's might change without the propshaft turning since the load on the engine will be lower (and thus it will require less fuel and less air to reach a given RPM).

Other thoughts: It's happening at 1K RPM but that acoustic frequency is much higher, so if it's rotational it's likely turning faster than the engine, which means something with a smaller belt pulley than the crankshaft. That suggests a bearing in the water pump (as someone else mentioned above), alternator, or other engine accessory.

I'm also not convinced it's not the propshaft throughhull, if yours is the carbon ring/stainless ring variety. I don't know what they were using in 1999; if yours is the older "packed gland" style then this won't be the problem. But if it's the ring style, your rings could have roughened mating surfaces and those can sing like that (as well as make lots of other really weird noises, especially if they get dry).

Try the transmission disconnect test and report back.

[mdk681]

Have you tried this with the transmission disengaged? As in, push the button on the throttle arm that allows you to rev the engine without turning the propshaft? I have a very slight but similar sound that is air resonating as it flows through the engine's spark arrestor. It only occurs at certain RPM's and I've heard it on other people's boats too. The RPM's might change without the propshaft turning since the load on the engine will be lower (and thus it will require less fuel and less air to reach a given RPM).

Other thoughts: It's happening at 1K RPM but that acoustic frequency is much higher, so if it's rotational it's likely turning faster than the engine, which means something with a smaller belt pulley than the crankshaft. That suggests a bearing in the water pump (as someone else mentioned above), alternator, or other engine accessory.

I'm also not convinced it's not the propshaft throughhull, if yours is the carbon ring/stainless ring variety. I don't know what they were using in 1999; if yours is the older "packed gland" style then this won't be the problem. But if it's the ring style, your rings could have roughened mating surfaces and those can sing like that (as well as make lots of other really weird noises, especially if they get dry).

Try the transmission disconnect test and report back.

Yes I have tried it with the trans disengaged, it did not make the noise during my test. It doesn't seem to happen when the boat is still heating up to temp. I am very familiar with the spark arrestor whistle - it is certainly not that. I have grown to ignore that noise over time and know exactly what that sounds like.

Watch the video again - when I am dropping RPM, the high pitched noise happens around 1300 RPM, kind of goes away around 1100 RPM, then changes to a lower frequency/pitched noise around 1000 RPM right at the end.

I replaced a leaky water pump a couple seasons ago, so I kind of ruled that one out. Not sure how I could pin point it to that or another pulley or the alternator... Also, when all of the work was done to my boat, the dealership replaced the prop shaft seal to a drip-less style. Not sure if that could be the culprit...

[IDBoating]

Thanks for the reply WRT the transmission.

Given you have the dripless seal, I suggest using a tool of some sort (I used a mechanic's stethoscope, cheap at Harbor Freight and super useful for locating sounds like this!) to gently touch the shaft seal in various places while the sound is occurring. That's how I found MY "weird noise" a few years ago. Touching the rubber boot and/or the carbon ring was enough to change the sound so obviously that all doubt was eliminated.

If not that, the stethoscope may help narrow it down by listening elsewhere.

[mdk681]

Thanks for the suggestions. I will certainly be getting a stethoscope and trying to track down the exact location the sound is coming from. Really puzzles me that it just started happening this season and nothing seems to be obviously wrong. Also that no one else seems to have as this issue either.


Sent from my iPhone using Tapatalk

[UNSTUCK]

The best stethascope is a broom handle. Place one end to your ear...