2006 Yamaha F250 Making Odd Noise...

[kshaf1962]

Hi,

Can anyone tell me what is causing this rattling...?...you can hear it come and go in the audio clip attached...(ignore water noise as boat is moving thru water/and transom door bangs twice in the middle of the audio clip)...?

You cannot hear this noise when the boat is idling in the water or in the driveway. And you can only hear it when moving slowing thru the water...e.g. no wake speed...e.g. 1000 - 1200 RPMs.

Cannot hear it at *****ing speeds...under more load...e.g. 1500 to 1800 RPMs.

Lower unit lube looks great...no water, discoloration, no metal shavings, etc.

No slop in prop, etc.

Sound seems to have gotten progressively louder over time.

Link to audio clip https://instaud.io/13FX. (not sure how to upload audio clip to forum)

[pstephens46]

How long have you had boat? Has it made this noise ever since you bought it?
Did the noise start after some sort of maintenance, i.e. water pump replacement?

[kshaf1962]

No recent physical maintenance...e.g. water pump, etc...just new fluids, lube prop shaft, etc.

I've owned the boat since 'new'...since 2007.

I do not remember hearing it in the past...just this season...my crew and I do think it is a new noise and seems to be growing more noticeable with each trip out.

It's odd...fading in and out like that...when I recorded this sound bite, we were on a lake moving in same direction...constant conditions...not variable like in an inlet going with or against tide, etc...with more load, less load, etc.

Appreciate the feedback and any help or insight offered. Thx.

[pstephens46]

I am not sure about this sound. Do you hear it in gear at idle speed?
Around 700rpm?

Wonder if a different prop would make a difference?

Can you borrow one?

[kshaf1962]

Yes...correct...in gear at idle speed is when it is MOST noticeable.

Using 3 blade SS prop, now...have always used this prop.

I'll put my alternate 4 blade AL prop on and see if that makes a difference...? Thx.

[panasonic]

Something rattling on transom bracket...maybe tilt locks? Have you had the cowl off and listened?

[kshaf1962]

Good inputs...keep them coming...I ASSumed it was stemming from the drive train...?...I'll pop the cowl, look around the tilt locks, etc. and see if anything like that is generating the sound.

Hoping it's something simple ! Thx.

[Emptynet]

What was the issue? My motor is making a similar noise.
Thanks.

[TownsendsFJR1300]

What was the issue? My motor is making a similar noise.
Thanks.

Can you try pin pointing it down to say the mid section.

Or with the cowl off, a screw driver to your ear and different parts of the block (under load-say idling in gear).
You could probably do this tied up to the dock (idling).

[99yam40]

both sound like heavy SS prop chatter

[pstephens46]

both sound like heavy SS prop chatter

Bump the rpm up to 800-1000 in gear and see if the noise disappears.

[Emptynet]

I pulled the boat out of the water tonight to take it in for service. I found that the trim tab anode bolt had stripped. The tab was loose and when I moved it it made the identical ratling noise. Problem solved. Thanks for the replies.