Still rattling
 

Just got the drive back from my mechanic. He took the drive completely apart again checked every gear bearing. It has a new input shaft new universal's new yoke, new drive shaft and cone clutch. He checked the pre load he said everything squeaky clean and for some reason the rattle still there At 800 rpm rattles 1000 rpm no rattle . If i remove the drive and start the boat no rattling
Any ideas
Thanks

I could be way off here but isn't it normal for cone clutch drives to rattle (chatter) especially when they're new ?
I remember mine did it quite noticeably when new and it eventually stopped .

I can't tell from the vid.
Is it gear rattle?
On cars/trucks;
If you replace a dual mass flywheel with a solid flywheel you'll get gear rattle.
So, could the coupler be hard as a rock from age, or a bit of spline wear and creating the same effect?

I don't hear it either. He said with the drive removed there is no noise so that eliminates flappers.

I would swap the drives side to side and see if the noise follows.

Hi, Thanks for all your replies, Watching the video i know its harder trying to listen on a video than seeing and hearing it in person, but besides the cam noise there is a rotating rattling sound not even with the cam..At 1000 rpm it disappears and when the boat is in the water off course nothing is heard. I noticed this noise last summer while rinsing out the engines after use.The other drive starboard does not do it. The y pipes are not being used. They are capped off. All exhaust and water come out thru transom. I think if i was a coupler you would here more of this noise inside the engine compartment.. The coupler and spline on the drive were greased, new bearing and a bunch of new drive parts...This all started last summer when i wanted the universal changed..That led to a complete new input shaft assembly because the mechanic said that one of the u-joint caps were slightly spinning in the center swivel yoke and shaft coupler. which BTY popped out and i almost didn't make it back to the marina. What a noisy racket having the cap on the ujoint pop up hitting the castle nut..WOW.So it was cheaper to purchase it completely then separate parts with labor.. Input shaft bearing checked, new seal, new washer and new lock nut..They checked the pre-load 6 times...used bearings i believe the book said 6-8 in lbs,.. I use Amsoil marine drive oil..It is clear..so when you drain it you can see if something is not right. the other drive is fine..
No unusual vibrations while cruising. Swapping drives...oh what a pain that is....? :readinghelp:

Mine do it.... its normal. just rebuilt both drives with fresh gears, new gimbal bearings, new everything...the rattle is normal...totally non issue.

yes

ok...my other drive doesn;t do it and 15 high performance boats at my marina don't do it

I Appreciate it.. we are a bit far./ I am near Westchester on the Hudson River

So we are pretty close then....I'm just north of Haverstraw Marina

Put your hand on top of the drive, you will feel a vibration from the shift fork cam bouncing up and down as the bump rings spin around and the space between the gears, moves up and down. Now shift it into gear. It should quiet down, as the linkage is holding towards the gear the cone is engaged with. Some make more noise than others, depends on gear stack, etc.

Hope that helps.
Dick

Update......I was out on 2 runs only this season so far and now the noise got much louder....No unusual vibrations felt...
check this out

I am going to suggest getting two 10' lengths of plastic downspout corrugated pipe (solid kind, not holes), and tape it up to your exhaust to help isolate the exhast/motor noise away from the drive when you are troubleshooting and filming.

I don't doubt you that you hear something in the drive. I can hear something in the video, but I can't discern any details about it.

buy a real doctors stethoscope. I have been using one for 15 years now. It is used for multi testing marine engines and noise testing , fuel pumps, fuel injectors, bearings in pulley's and of course outdrives, .

Wonder if its U joints. - When ever I pull all that assembly apart for changing U joints , I mark the shaft - yoke and input shaft . -- then put it all back together by the marks I made. Line to line to line. This keeps the balance of the assembly like how it was.

Pull the drive off --- stick a quality alignment tool in the coupler -- start the engine - How much of a perfect circle is the alignment tool making when the engine is running ? If not, then the coupler is warped or loose or coming apart. That could be the issue.

As mentioned swap the good drive over and then run the engine to see if noise goes away. If so, its a drive issue / or U joint issue. If not then no drive issue or no U joint issue.

I appreciate your input, good points...as for the coupler, Wouldn't there be a noise behind the engine if the coupler was the culprit.. I can stand in my engine compartment with engine running and i can get behind the engine. All i heard was the engine. but the knocking noise you can only hear while standing behind the boat and you can here it over the exhaust noise.. As for the u joints..I replaced the complete input shaft assembly.This comes with u joints, front shaft, rear shafr coupler, everything except the gears and bearings..They checked out fine...The only thing i notice now is the noise is louder. So i will be bring the boat to the marina and let my mechanic listen to it...Its hard to pin point it in the video..but listening closely there is a rattle besides the cam sound that is not even with the cam.

I had a drive do this once and it was the gimble bearing not tapped in far enough. was the strangest thing.

Possible unbalanced U Joint assembly -- yoke - input shaft - u joints -

Brought the boat to the marina mechanic, Started it up on the trailer for him. The noise is definately louder. he said sounds like a u-joint rattling and it got louder as i turned the wheel. The input shaft that was replaced was a complete new Sierra assembly. Maybe there is a difference between Sierra and Mercruiser. I decided to replace what was bad on my oem assembly. I just purchased a new oem yoke coupler and 2 new oem merc u-joints. Put it all back together.. One thing i noticed ..On the Sierra assembly before installation it seemed tighter than the merc assembly i just rebuilt. You maybe be right...something wrong with the Sierra unbalance or out of round etc
Next update after i change the input shaft assembly
Thanks

Hopefully I am not jumping the gun here --- but you do not have to say anymore Sierra assembly, It prob is an unbalanced assembly on top of and I am not kidding about that with Sierra. I have seen that before and more than once.. Also will add even seen where people with Volvo Penta SX outdrives change U joints only and the assembly becomes totally unbalanced. Thru OEM Volvo they do not sell the U joints alone you have to buy the the whole assembly even if it is one u joint bad a dealer going thru Volvo still has to buy the complete assembly. Their assemblies are completely balanced. Volvo --- thru them. Just saying

If you said that to begin with -- ( its a Sierra assembly ) I would have said swap that all back out to Merc assembly and see what happens. I would have done the whole assembly with Merc as it comes all together as well. .

It makes sense...The mechanic that was working on this suggested Sierra because it was 1/2 the price of the merc assembly...Live and Learn.. Hopefully this is the problem and hopefully if it is unbalanced it hasn't messed up anything else in the drive. So now i am waiting for my new mechanic to fit me in to change the input shaft. I will keep you updated. Thanks for the explanation

Another Update
 

Mechanic installed the Merc. OEM input shaft today..He said everything was squeaky clean inside the drive. Oil was clean (Amsoil Marine gear lube). Nothing unusual found.He put the drive back on the boat and i started it up on the hose....Same noise still there. he did mention that Bravos Rattle.....Ok I Give Up!
Anyone in need for a complete Sierra input shaft for bravo 1 with 10 hours on it......

Thanks for all the help here.https://cimg1.ibsrv.net/gimg/www.off...5ebb2d3514.jpg

Hope he pressure tested the outdrive after he put it all back together. The upper input shaft seal could have been compromised from an imbalance assembly.

So are you saying it is better but not 100 percent currently ? How much better is it ?

Its the same no change. He did pressure test it. I noticed a few scratches or marks on the center yoke and he also said he noticed that also but there is nothing in the area that can rub on that..The boot...?

How about trying another complete known good drive on the problem side? If noise persists then its from transom forward if noise goes away you know its drive associated.

Great idea, with all the work you have gone through already just swap your drives and see if the noise moves.

You might also want to do a cylinder balance test. Rough idle could cause a gear noise.

I agree with all...The mechanic mentioned that when an engine is running at idle it actually slows down and speeds up based on the compression stroke that can cause a rattling...First for me but at this point I would believe anything.. SO.. I will swap the drives ( what a pain in the _ _ _ _ )
Thanks for every ones input

Sounds like you might be ready for a new mechanic, or at the least a second opinion, no offense. Sounds like you are close to Clustergear, might reach out and have a conversation with him. Got to know him last fall. I replaced a pair of tired XR's with new and sold Clustergear the take offs. Guy is the real deal, has some serious history with Merc Racing, lots of hands on experience with drives. If I needed a drive fix I would take the drive to Lake George to see him. Just a thought on my part, he's a decent guy.

Many have said swap the drives and while they are off like I said stick an alignment tool in -- check the alignment and then run the engine to see if the alignment TOOL makes a perfect circle. If not like I said - bad alignment - or loose coupler or its coming apart. What do you have to lose at this point ? And that takes like 5 mins all to do since your pulling the drives anyways to swap over. At the very least I would check both couplers - looking maybe for some other issue that can be just starting as well.

I will do the alignment tool test before i swap the drives. I do remember removing the drive awhile back and starting the engine and there was no noise....I will keep you updated..I have to bring the boat back home to do all of these tests..especially because of the drive jack..what a savor lol...This noise has been there since last summer after messing with the u-joints.. I remember first when the clip popped out of one cap on the u-joint
as i just made it back to the marine. Putting the drive high up getting it on the trailer I heard an awful loud metal to metal noise. I immediately shut it down. Took the boat home and called the guy that put the u=joints in. It took us 1 hour to get the drive off because the u-joint clip popped out and the u-joint cap popped up jamming into the castle nut on the drive. Just a little refresh of what went down when all this started...But looking at the castle nut.. No Damage Was Found

I will keep in touch Thanks

Update!
 

I pulled the noisy drive off and did the alignment bar test.. Looked fine to me (see video). Then i mounted the noisy drive on the other motor (startboard) and the noise was there. So the noise is in the drive. see attached video. I then pulled the top cover off and rocked the top gear back and fourth...This is the noise i am hearing while running.. see attached video.

Any suggestions???

Can you send me his name and #..
Thanks

no flappers...straight out transom

Great idea but i used some large towels instead..

update!
 

I sent 6 videos to Mercury Marine..They said they couldn't hear it from a video..But they said check the top cap bearing and if you haven't ever changed it, you should just be careful on the tower height. Also make sure the + - are lined up perfectly on the gears. top minus bottom plus or visa versa, and something about the shift linkage adjustment. They also mentioned something about when the engine comes around on the compression stroked it actually slows down and speeds up even if we don't hear it and even though the engine is spinning smoothly it can cause a rattle, an engine that is tuned differently or needs to be adjusted. I told him I have 490 hp and i have the only boat out of 12 performance boats in my marina with this noise and the other 12 boats have a lot more hp than i do.They mentioned boats with transmissions that have a clutch plate rattles. I believe i mentioned something about this in a prior post. I swapped the drives and the noise followed the drive. My other drive is quiet, so i will cut out the rotation of the engine diagnoses.
Took the boat out yesterday...no vibrations..Hit some big rollers, came out of the water a lot.. Put the boat on the trailer, started it up and the noise was a bit louder I guess from the oil thinning out.

Well, thanks for all the input from everyone..It was a good try..Hopefully the drive stays together. Does anyone need a complete input shaft assembly..Cheap 10 hrs on it.. here's the link Thanks Jay
https://www.ebay.com/itm/263814894879

Got it thanks
J