What is this strange noise

[Lawtonfagiano]

I have a 2003 yamaha vmax hpdi 200. The engine starts and runs great but has been making the noise present in the first video linked below for several months now. It only makes the noise when in gear, and goes away at higher rpms, and its performance has remained consistent throughout the year. The noise in the video is about as loud as it will get, but on occasions it is quieter. The second video linked below shows the engine at neutral idle, and the noise is not present. I know this type of engine only idles on 4 of 6 cylinders when in neutral, not sure if that has anything to do with the noise. My first thought was that it was some sort of internal engine noise, but I'm really hoping that's not the case. I know it's not prop rattle as I've run it without the prop and it still makes that noise. I was thinking maybe it was the clutch dogs rattling at low rpms maybe. Any ideas on what it could be?

 

[robert graham]

Probably just a normal 2 stroke outboard rattle....my old C90 makes a few noises that are hard to identify.....guess this is why folks love the modern/quiet 4 strokes.....

 

[alldodge]

Gear lube look good?

 

[QBhoy]

I’d check that prop and how it’s fitted. Is the thrust spacer there ? Can you move it on the shaft excessively? Is it hitting a trim anode fin perhaps.

 

[crazy charlie]

Hard to tell from video sound anything outside of regular engine noise. I Had some engine noise develop that sounded more like a tapping or ticking .Yours may be same but louder.See if it is significantly louder with engine cover off...mine was.The issue was simple to address and correct.With a 10mm socket and small extension remove the O2 sensor housing .Some models you will have to remove the O2 sensor but on my SX200 the entire housing removed pretty easily,only about 6 bolts if i remember correctly.Inside the housing is a horizontally installed small silver stud.Mine resembled a tiny silver dumbell weight .Pull it out of the housing and carb cleaner soak it or wire brush it clean.There is a hole running down the center that is usually clogged shut.You can run a small drill bit through it to clear it.This eliminated my issue.You can also clean the O2 sensor while at it.10 minute job and should be done anyway.Basically clogged exhaust.Give it a try and post back.Charlie

 

[Lawtonfagiano]

The prop and thrust washer all look good. I will check gear lube and the o2 sensor tomorrow.

 

[QBhoy]

The prop and thrust washer all look good. I will check gear lube and the o2 sensor tomorrow.

Sounds good. What prop and hub kit is on it ?

 

[Faztbullet]

Sort sound like a Opti compressor about to take a chit...check high pressure pump? Check belt tensioner and roller?

 

[Lawtonfagiano]

Drained and checked lower unit oil yesterday and it looks good, no metal shavings or anything. Cleaned the o2 sensor as well, it was dirty but not terrible. The noise is still present. I never thought about the high pressure pump or the high pressure drive belt. I will check the belt tension and gear oil in the pump tomorrow.

QBhoy I have power tech 4 blade prop on it.

 

[crazy charlie]

The 02 sensor was not where the noise can come from.I was directing you to an very small passageway just to the left of the 02 sensor.A very small silver barbell shaped piece that you take out with your fingertip and clean thoroughly especially the passageway through the center of it.The actual 0s sensor should also be cleaned but thats not what I was directing you to do.This issue if not corrected will cause a "lean burn" issue which you DONT want.Did you see the piece I am referring to?? Charlie

 

[crazy charlie]

Do a youtube search on this exact...

Yamaha Outboard HPDI O2/ oxygen sensor cleaning/replacement/removal​

its a perfect video of the service.I will try to post a link for you.https://www.youtube.com/watch?v=2khBAHmiLVQ Charlie