Boat Noise while riding.

[LukePrinsloo]

2011 AR240, 215 hours.

So I bought my boat after a test drive. I had heard on here that the boats were noisy and just accepted that the noise was normal. After discussing how disgusted I am that a boat can be this noisy I took a video and shared it with some friends that have Yamaha's. This cannot be normal. Please see my video below from a trip recently. I am not sure what speed we are doing but it's <20 mph.

I have replaced one of the intermediate shaft bearings already and had a slight reduction in vibration in the boat. I have greased the other and intend to replace it this winter. The pulled bearing housing was leaking grease/water mix. However when I rotate it by hand it spins freely and appears to be in fine shape.

I have pulled the pumps and saw that the cones appear fine. They are "stiff' but rotate without binding or any feeling of drag, just takes a bit of force to rotate.

I also reviewed the pump cases and saw no corrosion/liner wear.

Jet impellers appear pristine.

Shaft to the impellers is a blue hue like it's been heat treated.

I replaced the spark plugs and have gone through two tanks of fuel.

Cleanout plugs were pulled and replaced.

 

[buckbuck]

Aint never heard a Yamaha sound like that.

 

[Noko]

Sounds like some internal vibration. Something could be loose in the engine bay or it could be one of the panels that closes off the engine bay from the storage areas next to the engines.

 

[haknslash]

Dang that so loud it interfered with the camera! Never heard one that loud either.

 

[Gym]

Did you pull the rear cones to check the bearings? Also look closely at the impeller liners to see if the impellers are making contact on any part of the liner. This could be hard to see and may only show as a couple of dark spots. You may have swelled liners. My other concern is the blue hue you see on the shaft near the impeller. That sounds like someone used heat to remove an impeller. There is a possibility you have a bent shaft causing the vibration. This may have been as a result of the previous owner overheating or using too much force to remove a previously damaged impeller.

 

[LukePrinsloo]

Did you pull the rear cones to check the bearings? Also look closely at the impeller liners to see if the impellers are making contact on any part of the liner. This could be hard to see and may only show as a couple of dark spots. You may have swelled liners. My other concern is the blue hue you see on the shaft near the impeller. That sounds like someone used heat to remove an impeller. There is a possibility you have a bent shaft causing the vibration. This may have been as a result of the previous owner overheating or using too much force to remove a previously damaged impeller.

As per my OP: Pulled the jets and inspected them. I also can see that the impeller is not touching the casing ( you can see the gap all the way around the impeller.)

I did not take the cones apart to inspect the bearings. I was not aware you could do this.

I had not thought about a bent shaft. Both impellers are the stock 6AP10 impellers and look brand new. I always thought 200 hours or so new, but now you have me wondering if they are BRAND new. (see how discolored the housing is next to the impeller?) The boat was supposedly on a lift it's entire life, but the corrosion marks have me questioning that.

of Note: the buzzy sound you hear when I pause each time is the phone against the hull on each side. The noise is "SLIGHTLY" louder on the passenger side of the boat. Vibration is somewhat stronger on that side.

Guess I need to figure out where I put my dial gauge and try measure the shaft eccentricity.

 

[Scottintexas]

I would run then engines without the shafts to help isolate the noise and rule out an engine issue

 

[LukePrinsloo]

I would run then engines without the shafts to help isolate the noise and rule out an engine issue

I did this without the pumps the first time and that is why I replaced the intermediate bearing on that side. When I replaced the bearing I ran that motor w/o the bearing and itw as MUCH MUCH quieter.

I can do 50 mph indicated and the boat is a screaming demon which leads me to assume that the motors are not hurt.

 

[Jgorm]

I'm also in the bent shaft theme. Probably need new bearings again if the shaft is out of round.

 

[Gym]

It may be just the pic but it looks like a slight bend in the shaft where it turns from blue to black.

With regard to the cone bearings there should be 3 Allen bolts to remove the cone to inspect the bearings. If you had a bearing issue it would sound more like a bunch of marbles rattling around in a tin can. I still think it's a bent shaft.

 

[LukePrinsloo]

Not sure how it never occured to me to check but I think several of us are in agreement on the shafts possibly being bent.
If the shafts were damaged on install, I wonder what else was damaged... Seals in the wrong order etc.
I'll pull the shafts on Friday and put a straight edge to them. I need to find my dial caliper but it's been ages since I last used it.
I've straightened motorcycle forks in the past wonder if it is possible to do the same for the driveshaft.
I'll also pull the cone cap and see how the bearings are. As you said, I would not describe this noise as bearing failure. I replaced the INT bearing because even with the shafts pulled I had substantial noise coming from the one engine. When I pulled the Int bearing/int shaft out I rebolted the engine down and started it and it was buttery smooth. That sound did sound like marbles grinding in a can.

The passenger side is the one with a "feel" of more vibration than the driver side. so I'll start there.

 

[biffdotorg]

Sorry, I had not seen this thread before your other post Luke. How much is a new shaft?

 

[LukePrinsloo]

ypw has it for about $300, but then I need a special tool, and seals, etc.
So probably $500 a side is my estimate.
IF it's bent.

 

[LukePrinsloo]

So happy news. It's not bent. Like at all, Neither shaft. I put a straight edge to them, then put the pump in a vise and ran a dial gauge on it while rotating it at the bearing.
Bearings look good too, the proper mix of oil and grease is present with no signs of water. Waiting on my phone to upload the pictures.
I rode in another boat this weekend and the exact same vibration is there. Guess you can just call me sensitive and I guess teh phone picks it up stronger than anything else.
I also took a ride in a newer 2015 with 60 hours on it (test drive), vibration is there; can feel it in your feet when standing on the rear deck but none of the audible noise is present. All I can gather is that what I feel is excessive is normal for the older boats.
As such i'm putting the 2011 up or sale; I've found a 2015 with all the upgrades i wanted to do with this one. (seadek, jl audio setup, underwater lights). I rode in it this weekend and it was fantastic.
Note I did touch the phone to the deck on both sides in the video I think this amplified the noise it made.

 

[swatski]

So happy news. It's not bent. Like at all, Neither shaft. I put a straight edge to them, then put the pump in a vise and ran a dial gauge on it while rotating it at the bearing.
Bearings look good too, the proper mix of oil and grease is present with no signs of water. Waiting on my phone to upload the pictures.
I rode in another boat this weekend and the exact same vibration is there. Guess you can just call me sensitive and I guess teh phone picks it up stronger than anything else.
I also took a ride in a newer 2015 with 60 hours on it (test drive), vibration is there; can feel it in your feet when standing on the rear deck but none of the audible noise is present. All I can gather is that what I feel is excessive is normal for the older boats.
As such i'm putting the 2011 up or sale; I've found a 2015 with all the upgrades i wanted to do with this one. (seadek, jl audio setup, underwater lights). I rode in it this weekend and it was fantastic.
Note I did touch the phone to the deck on both sides in the video I think this amplified the noise it made.

I did not read everything carefully, but I have been fighting the noise in my boat, have had some success lately. Wiht the swim deck, stuffing of the space with the premium carpet under-mat (hydrophobic foam/plastic) has helped - post #8 https://jetboaters.net/threads/fill...ng-foam-good-idea-bad-idea.17966/#post-308015

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[Gym]

I'm still curious as to what caused the discoloration on the shaft in your pic. Looks like a lot of heat was applied. Were the impellers changed at some point or are they origional?

 

[LukePrinsloo]

@Gym I honestly have no idea.
The shafts have no tool marks on them where you'd expect to see some if the impellers were changed.
The prior owner had mentioned getting a rope stuck int he jets. I wonder if he melted the rope to the shafts.

 

[Gym]

@Gym I honestly have no idea.
The shafts have no tool marks on them where you'd expect to see some if the impellers were changed.
The prior owner had mentioned getting a rope stuck int he jets. I wonder if he melted the rope to the shafts.

Ahh, the rope scenario sounds plausible. Not sure if it was mentioned but is it possible the rope may have removed or loosened some caulking around the intake grill? That would definately cause cavitation.

 

[LukePrinsloo]

Honestly that may be it. There is no silicone other than around where the shaft enters the hull.

 

[Gym]

The silicone I'm referring to is under the boat. It's applied around the intake grate to prevent cavitation. Several members who have sucked up ropes have lost some silicone around the intake grate. You can get under the boat to visually inspect it.