Damper plate upgrade

[Molarbu]

Ruffdog is right on. A harmonic noise is something that would happen in a repetitive pattern based on the frequency of the part generating the noise. The repetitive pattern would increase or decrease as the vibrating "source" part's vibration increases or decreases (ie as the throttle increases or decreases in this case). Sometimes the harmonic noises will go away at a certain frequency or above a certain frequency.

Think of two sine waves of the same amplitude that are out of phase. The points the two waveforms cross would be a harmonic. If the frequency of the waveforms increases, the number of harmonics (intersecting points of the waveforms) would increase over a given time period.

Aaahhhhh, that cleared it up!

[DUKENO1]

Aaahhhhh, that cleared it up!

Ahhhh, I get it! It sounds just like the sound two sine waves make when intersecting each other! Then I just have to

take the square root of the hypotenuse divided by ohm's law and I should be good to go!

Thanks!

[martinarcher]

Sorry fella. I'll remember to check my engineering self at the door.

[John23LSV]

Sorry fella. I'll remember to check my engineering self at the door.

We have some engineers on board, nice explanation. I just like to think of it as the noise that shouldn't be there. If all you hear at idle is a smooth engine idle and when you put the boat into gear, it is still idling nice with no additional noise, it is normal. You will know it if it doesn't sound right.

[footnlongline]

I don't know how else to explain it....ever travel in an old car really fast on the freeway? It is that noise that the car makes, kind of cyclical in nature.

Someone else might have a better explanation.

I left my geetar to close to the amp and forgot to turn the amp off, well, the thunderstorm caused the geetar/amp combo to start harmonizing into what I considered to be harmonic noise. The noise reminded me of this damper plate thread Yee ha!

[JAGMAN]

Is that the original carpet in that 2000?

Sweet boathouse. Beautiful...

[GreenMan]

Ahhhh, I get it! It sounds just like the sound two sine waves make when intersecting each other! Then I just have to

take the square root of the hypotenuse divided by ohm's law and I should be good to go!

Thanks!

Might be like connecting a Discombobulating Fractionator to the input of an Electronic Vectorial Runout Compensation Unit. Could be worth getting the Static Regain Inverter re-calibre-ated.

Either that or find out which component's resonant frequency is actually being excited.

No, no, don't thank me. Your welcome!

Edited August 15, 2011 by GreenMan

[ajinid]

Question: if I don't have access to equip for lifting the engine, could I just as easily empty and remove

the gas take to get to the damper plate?

Edited July 30, 2012 by ajinid

[coyote055]

Question: if I don't have access to equip for lifting the engine, could I just as easily empty and remove

the gas take to get to the damper plate?

My Vride has exhaust parts in the way along the transom so the mechanic that's working on mne is going to try to get to the damper plate by removing the fuel tank. I don't see how he can do it without also removing the seat base, but I'll let you know how it works out.

[ajinid]

Anyone know the difference between the Skidim plate and the Indmar updated plate? Does the Skidim plate have spings that can fail?

Coyote055, how did it go upgrading your plate via fuel tank removal? (BTW, I ski Cottage Grove reservoir and Dorena once in a while).

AJ

[Slayer]

I want to bring this thread back.

I have been hearing a much more audible "clunk" when going into gear on my '97 SSLX. I have also noted an interesting harmonic type of noise above idle speed but it's inconsistent. I'll try to get a video so the sound can be heard. Is it possible that this is a damper plate getting ready to let go on me?

[Lance B. Johnson]

Can these be diagnosed by pulling the starter and taking a peek?

[tvano]

i don't think so. you may be able to touch the flywheel if you pulled the starter.

maybe, if you're lucky, you could touch that part of the damper that bolts to the flywheel.

i don't think you would be able to assess the play between the sprung and un-sprung damper pieces.

[Slayer]

I think tvano is right. I think it needs to be torn apart to confirm.

[Lance B. Johnson]

i don't think so. you may be able to touch the flywheel if you pulled the starter.

maybe, if you're lucky, you could touch that part of the damper that bolts to the flywheel.

i don't think you would be able to assess the play between the sprung and un-sprung damper pieces.

sweet, that makes this whole issue even more awesome

[coyote055]

Can these be diagnosed by pulling the starter and taking a peek?

I have to wonder if you couldn't get an inspection camera in the starter hole and around the flywheel to take a look. I just saw them at Harbor Freight for under $100.

As a side note, my mechanic decided that lifting the engine was the way to go for replacement.

[rivvyc]

I believe I have the same issue. I plan to video it this week and post. I have a 03 response lxi w 335 monsoon. I am guessing w my direct drive I wouldn't need to pull engine? I could probably separate tranny and have access. More to come... Definitely a great article. Thx

[tvano]

I believe I have the same issue. I plan to video it this week and post. I have a 03 response lxi w 335 monsoon. I am guessing w my direct drive I wouldn't need to pull engine? I could probably separate tranny and have access. More to come... Definitely a great article. Thx

correct. you can loosen the front motor mount and lift the rear of the engine to gain enough space to pull the transmission.

[rivvyc]

Thanks. I will get a video on Friday and let you experts help me nail down this is my issue! The articles have definitely given me the confidence to do the job if I need to.

[rivvyc]

Is it common for the rotational klunking to only happen when it is in gear? My boat doesn't make any noise until you run it in gear at low rpm's.

[Kenw]

Is it common for the rotational klunking to only happen when it is in gear? My boat doesn't make any noise until you run it in gear at low rpm's.

Yes

[tvano]

when my oem damper plate was failing the noise only occurred at idle in gear.

the pos replacement damper plate is failing now and the noise only occurs at idle in neutral.

[rivvyc]

Sounds like the heavy duty Skidim is the one to go with... How many hours do you have? I have 720.

[tvano]

i emailed skidim a few weeks back. they don't carry a heavy duty replacement damper plate for the LCR engine.

i didn't have very good luck with the sach's brand replacement. it started to make noise after 110 hours of run time.

[norcal_rdr]

Tvano - We have gone through 2 damper plates in year due to the same/similar noise noted above. The second replacement came about 75 hours after the first and was the heavy duty from Indmar. It made a noise that was louder and worse than the original noise but Indmar swore it was because of the heavy duty nature of the part. Low and behold 50 hours later (less than 4 months) we have a cracked crankshaft and full motor rebuild. Just took the boat out for the first time since the new motor and noise is gone. Our mechanic believes the crankshaft was the issue the entire time.

Just want to throw it out there, it might be worth digging a bit deeper than just assuming another damper plate failure. Best of luck (or at least better than mine)