Yamaha F90 strange noise

This is kind of a hard problem to describe but…
At an idle and above 2K RPM’s my motor is nice and quiet. But between about 1500 and 2K there is a whine/rubbing noise that is very prominent. I am thinking it is something to do with the belt or maybe a tensioner? Strange to me that that is the only in that range of RPM that it can be heard. This occurs both going up in RPMs and Back down.
I have not yet pulled the cover and investigated when in the water but was hoping someone else might have experienced that same thing.
Motor is operating normally otherwise.
I attached a video and you can hear it but it seems much louder in person.

Thanks

Attachments:

1. motor-noise.mp4

What year is your motor??
I’ve got an idea of what it is but I need to know the year to be certain before I mention anything.

IOWABOY1 its a 2011

Dive shaft needs grease
Take lower unit apart grease the spline slide it back on..

Just change the water pump a month ago period greased everything when I put it back together. Is it possible I did not do enough? I coated everything.

Give me a few, I have to finish my day here at the shop and I will look into it for ya.

Iowaboy1 has been in contact with me and we are working through a few tests to see if we can id the issue. I will post the results when I can.

This is what I have done so far.
!. Taken Iowaboy1’s suggestions…LOL THANKS FOR THE HELP
2.Checked the lower unit for oil. If low could be a dry bearing in LU.
found it to be slightly low and as it should so filled it up.
3. Took the prop off and noted that the nut didn’t seem as tight as it should have been. Started the motor and put in gear to check the out shaft for straightness. No movement.
4.Ran to problem area RPM’s but could not replicate the sound in with LU NOT engaged.
5.Put in gear and repeated with same result.
6.Took the motor cover off to check for water leaks found none.
7. Installed prop and torqued to 45# and repeated steps 4 and 5 same results

So next thing to do is get it in the water and try it again. I also am to check all mounting bolts to ensure everything is tight and not creating a vibration/harmonizing sound.
Iowaboy1 thinks that if it comes back when in the water, it may be a bearing in the LU. Which under pressure from the prop would start the condition. If it comes back I am to drain the LU and inspect for metal in the oil.

THANKS ALL FOR THE SUGGESTIONS! I will keep you posted but it looks like it will be next week before weather clears enough to try it out.

Attachments:

1. 344444392_23971739432425072_7080373577332211000_n.mp4
2. 344270091_6103021943126869_9040401588655048721_n.mp4

We will sort this out even if we are 300 miles apart!!!

Iowa boy is the man!

Gitchi Gummi wrote:

Iowa boy is the man!

I have a 2012 F90 that’s making a similar noise between 1,000 and 1,500 rpms’s. I read elsewhere that it could be the driveshaft busing getting dry. Removed lower unit and greased the driveshaft bushing but didn’t make any difference.

Attachments:

1. 20230418_124952.mp4

A few things I’ve seen cause similar noises on competitor engines.

Impeller housing contacting the driveshaft. This normally doesn’t just happen randomly, instead it seems to pop up after a impeller replacement.

Prop has a bad finish or defects on the trailing edge of the blades. Try wrapping tape around the trailing edge of the prop. If the sound changes pitch or RPM range you’re on the right track. Mercury actually had a service bulletin on this back in the 90’s.

Flush check valve vibrates at certain pressures. You can simply hold the check valve in your hand while the engine is making the sound. If it goes away your on the right track. I had one that I simply zip tied the valve off to something else under the cowl which fixed it until a new one could be ordered. This one did act up in and out of gear, and of coarse is only a possibility if the engine has a flush port from the factory.

Thanks, I’ll check those things out. The ringing noise is very annoying. I’m hoping it’s not a bearing somewhere. There’s no vibration and it only happens between 1,000 and 1,500.

Yep thats a GREAT recording of the sound. That is exactly the same as mine.
I was not able to water test the motor due to maint on the pull vehicle but plan on trying in in the next day or so. I did find that my prop is a low quality prop and one of the fins is not the same as the others and where the hub and fin are attached is very thin compared to the old prop I took off that is damaged. What I might do though is put the old prop on jsut to test and see if the noise goes away. IF it does then I know the problem. Stay tuned

Hillhiker I will add those to the list of things to check.

trwhit56 wrote:

Thanks, I’ll check those things out. The ringing noise is very annoying. I’m hoping it’s not a bearing somewhere. There’s no vibration and it only happens between 1,000 and 1,500.

Im with you on that one.

I had that same issue years ago, about 2011. Local boat guys didn’t know what the noise was from. Next time I was in the shop talking about the issue a Yamaha rep over heard the conversation and knew exactly what the issue was, local guys did not. It was I believe an incorrct size plastic bushing and when replaced with the correct part have had no further issues.

dentedboatguy wrote:

I had that same issue years ago, about 2011. Local boat guys didn’t know what the noise was from. Next time I was in the shop talking about the issue a Yamaha rep over heard the conversation and knew exactly what the issue was, local guys did not. It was I believe an incorrct size plastic bushing and when replaced with the correct part have had no further issues.

Ok thanks for posting but Where was that bushing?

I do not know as I am not an engine guy. However I think I later saw a photo of this bushing/bearing somewhere omline. I am sure you could find the photo somewhere. It might of even been on this site or a boat/engine magazine. Google Yamaha squeaky bushing and I bet it will pop up.

I’ve heard the drive shaft bushing being the cause of something similar, but mostly on larger engines. I just did a search and see people have complained all the way down to a 60HP. Good call dentedboat.

I pulled the lower unit today and cut out the driveshaft bushing. Going to try it tomorrow without the bushing and see if that was it.

Well that wasn’t it. Still have the same noise. There’s an opening right behind the steering section where you can see the driveshaft turning. I also sprayed lots of silicone on the driveshaft there while it was running but had no effect.
Sounds like a bearing. I guess it’s going to the shop next.

question
Did you let it warm up or try it cold? I just went and dipped mine on the trailer and the sound was not present at any RPM.
BUT after getting home I had the thought that maybe I should have let it warm up and try it again.

Not sure if it applies to your motor, but I know the bigger Yamahas had problems with the harmonic balancer?

OK for some reason this site locked me out and couldn’t reset password so I’m back as trwhit57. I put my boat in the water and ran it for 15 minutes or so. The noise was present right off the bat at same rpm range. One thing I noted is that if you turn the motor all the way left or right the noise goes away but comes back as soon as motor is straightened out.

I had a Yamaha mechanic listen to the video and the first thing he said is driveshaft bushing needs grease, which I have already removed. Only other thing he could think of is maybe the metal cup in the water pump might be rubbing the driveshaft. Took that apart and it is not rubbing. At a loss for what to do now except just live with it.

I am no mechanic, by trade anyway, but I do believe that the Drive Shaft bushing is UNDER the water pump. And I believe you can not run without it because the water would contaminate the LU oil.

If the weather ends up being a washout tomorrow I might pull the LU and see if I can get the Key out of the keyway and try to grease it.
But I need to ensure that all the things I have done hasnt fixed the issue. At least mine.

You’re thinking of the seal that is under the water pump. The driveshaft bushing is actually about 6-8 inches up in the mid section. After you remove the lower unit you can look up in there and see it. It has a snap ring holding it in but mine was stuck in there and had to cut it out. It’s a brass ring with a rubber sleeve. Item 23 in this parts diagram.

https://www.simyamaha.com/parts/use-parts-diagrams-to-order-parts?year=28&model=1758&category=13

Attachments:

1. 

   67f-45318-00.jpg
   

See told ya. I am no mechanic by trade.
BUT COOL!!!! I was looking for a schematic just like this.

Here’s the diagram for the lower unit and water pump.

https://www.simyamaha.com/parts/use-parts-diagrams-to-order-parts?year=28&model=1758&category=49

I’ve been reading a lot of posts of propellers causing whine or ringing. I have a sneaky feeling it may be that. Last year I replaced a broken prop with an aftermarket one. Didn’t use boat for a couple months. Noise might have started after that. Anyway I’m going to put the original Yamaha prop back on and see if that’s it.